Energy Transformation Field: Infinite spells

[Cruiser1]

The 7th level Sor/Wiz spell Energy Transformation Field from SpC is one of the most powerful spells available. There's a good reason why it's banned in many games or contests such as the Test of Spite (http://www.giantitp.com/forums/showthread.php?p=6885277). However in a game world where it's available, there are many ways to take advantage of it in theoretical optimization.

Energy Transformation Field allows you to store any spell within it (which is presumably cast into it at the same time the field is cast, similar to Contingency). Afterwards the field will absorb all magic in the area (including spells cast, Sp and Su abilities used, and magic items activated) and use those spell levels to power off instances of the spell stored within. Because the spell is Permanent duration, effectively you cast a spell once, and can reproduce it an infinite number of times. You don't want to cast your own limited per day spells to power it, but rather you want to use an at-will spell-like ability, or a freely activatable magic item like the Immovable Rod which adds two charges each time you click it (because it's based off a 2nd level spell).

There are no limits on the "single spell linked to it" that can be put into an Energy Transformation Field (other than it can't have XP or expensive component costs). It says the spell is "cast at a point within the field designated by you", which implies even Touch or Personal range spells can be associated, which get cast upon whoever is at the appointed location when the field’s spell is activated. This makes Energy Transformation Field one of the few ways to get Personal range spells cast on other targets. Other ways include the Share Spells ability for familiars and animal companions, Glyph Seal magic items from MIC, Bracelets of Spell Sharing magic items from DMG2 to cast on you and a partner, and Shapechanging into a Symbiont and latching onto your target to share spells with them.

There are also no limits on the level of spell that can be put into Energy Transformation Field. Go ahead and use your metamagic reducers to put in an Extended Persistent Shapechange (http://www.d20srd.org/srd/spells/shapechange.htm). Then have an army walk through while you click your Immovable Rod to give each person a two day Shapechange. Give the enemy army quite a surprise when all your troops suddenly turn into something very nasty! The only limitation is that (like Contingency) all spell choices are decided ahead of time. Hence you can't place a spell like an illusion (unless it's always the same illusion), or Polymorph Any Object (unless you are always polymorphing targets into the same thing).

Clicking an Immovable Rod will take 5 clicks to activate a 9th level spell. A Ring of Telekinesis (based on a 5th level spell) will add 5 charges and hence take 2 usages to activate a 9th level spell. However the fastest way to activate Energy Transformation Field is with a magic trap (http://www.d20srd.org/srd/traps.htm#crMagicTrap). An automatic resetting trap of Magic Missile at 1st caster level costs 1200 gold to buy. (It costs 500 gold and 40 XP to craft, where 500 gold x 2 + 40 XP x 5 = 1200.) Create 9 such traps, each attached to a lever with a larger lever or floor plate that activates all nine at once. Place it in the field, and you can walk in and as for what amounts to a move action activate all 9 traps and all 9 spells, and hence cast the associated 9th level spell for free.

Energy Transformation Field is stored at a fixed point in space, which normally means you can't take advantage of it while adventuring unless you teleport to and from it. To get around this, cast it inside a Bag of Holding, so you can carry it with you, and more importantly be able to close the bag to effectively turn it off when you want. Stick your 9 traps of Magic Missile on a small item inside the bag. Then you just open the bag, reach in and press the button to activate the traps, which get transformed into a 9th level spell cast for free. A good buff choice is Maximized Time Stop (http://www.d20srd.org/srd/spells/timeStop.htm). Each time you click, you get 5 free rounds of time. Click the button once for 30 seconds of free time, or click it 120 times in a row for what amounts to an hour long Time Stop.

Fields allow a Sorcerer to extend their spells known relatively cheaply, to help overcome their Tier 2 limitation. A scroll of Energy Transformation Field costs 8525 gold (2575 for a 7th level scroll + 5000 material component + 250 x 5 XP). A Bag of Holding 1 costs 2500 gold. A custom Runestaff of a 9th level spell (and a throwaway 1st level spell since Runestaffs must have 2-5 spells attached to them) costs 16300 gold. This allows a Sorcerer to be able to cast a 9th level spell for 27325 gold (and without using your own spell slots). Actually cheaper than that, since you can sell the Runestaff back for 8150 gold as you only need it to cast the spell once to store in the field, or better yet just buy a scroll or hire another caster to cast the spell for you. That's much cheaper than a 102000 gold for a 9th level Siberys Dragonshard in a 1 slot Drake-Helm.

Energy Transformation Field allows any caster to have infinite spells. Another good choice for a spell to put into a field is the 9th level spell Absorption (http://www.giantitp.com/forums/showthread.php?t=212739) (SpC). Put a Maximized Absoprtion in the field, activate it, and you get 10 spell levels which you can use to cast any spell you know. In other words, reach in your Bag of Holding and click the button as a move action to activate the field and get Absorption cast on you. Then draw your special trapped item outside of the Bag of Holding and click it again as another move action to get yourself targeted by 9 Magic Missiles, which converts the Absorption to 9 spell levels you can use to cast any spell you want. It's effectively infinite spells! :smallbiggrin:

Combine free Time Stops with free Absorptions (in two Bags of Holding with Energy Transformation Fields), along with the ability to cast Miracle (http://www.giantitp.com/forums/showthread.php?t=200669) (such as because you're a Cleric, an Arcane caster with the Luck Domain, or an Arcane Caster with 10 levels of Rainbow Servant), and you can do what amounts to the Team Solar (http://www.giantitp.com/forums/showthread.php?t=188138) buffing trick with a single character, using infinite Miracles to give yourself every buff of 7th level and below of every class (8th level and below if it's on the Cleric list). And all in a single round! :smallcool: Single round buffing is one case where the Spelldancer PrC for metamagic reducing (where you dance on your own as much as you want to reduce metamagic) works easier than Incantatrix (where you use Body Outside Body clones to avoid the per day limits), because Time Stop only affects you and not other entities such as your clones.

Fields can be used offensively! If you can cast one near an enemy caster, or trick an enemy caster into moving into a location where Energy Transformation Field has been cast, it's effectively an antimagic field that completely disables all their spells and activatable magic items. Smart casters may have Contingency set up along the lines of "if I'm about to be affected by an antimagic field". Optimized casters also have ways to still cast within an antimagic field, such as the spell Invoke Magic or having the feat Initiate of Mystra. However, there are no ways to cast inside Energy Transformation Field, and few think to include that spell in their Contingencies. Since Energy Transformation Field is a spread instead of an emanation like the Antimagic Field (http://www.d20srd.org/srd/spells/antimagicField.htm) spell, you can't hide behind a tower shield to give yourself cover from it, and it won't activate tricks like a Shink Item'ed giant conical hat that you use to protect yourself by automatically generating cover in case you step into an antimagic field.

[Mystify]

Wow, I did not look at that spell close enough.
Once again, wizards takes a neat concept, and does not think its consequences through properly. Its clear what the spell was intended for, namely magic absorbing traps, but they neglected to consider its potential role in other applications.

Another use would be to attach mage's lucubration. Now your wizard has unlimited uses of his 5th level or lower spell slots. Go in, pump your lever, and recharge all those used spells. And since teleport is a 5th level spell, you can teleport to your ETF(assuming you aren't hauling it around in a bag of holding), recharge all your spells, then teleport back, an be down 1 5th level spell, and 1 return teleport spell. Though that does have miss chances to deal with.

Its not as powerful as the absorption, but while we're listing abuses...

combine the absorption trick with a rainbow warmage (or similar build). Hello to unlimited casting of every cleric spell at will.

[ILM]

That's not the worst of it though. Place two overlapping fields keyed to different spells of the same level. The only restriction stated is that "If 2 or more fields share an overlapping area, each field has an equal chance of absorbing a spell effect in that area." So you click your rod until one of the fields activates; it casts its level X spell, which conveniently is enough to activate the other field, which casts its level X spell, which activates the first field...

Instant casting of two (instantaneous) spells an infinite number of times.


edit: Another one? Okay, but this one may not be as clear cut. Find a way to repeatedly and infinitely activate an ETF - self resetting trap works, for instance. Make sure you created your ETF under a tree. Get an Acorn of Far Travel from that tree. From the description of ETF: "Spells that require will target the living creature nearest to the field." From the Acorn: "As long as you carry the acorn [...] you are considered to be standing under that oak tree's canopy." Consequently, you're considered to be standing under an oak and that oak is in the middle of the ETF. Likely there's nobody closer than that. So for instance, if you keyed your ETF to a Heal spell... you'd be getting free, automatic Heals all the time, wherever you are.

[Mystify]

That's not the worst of it though. Place two overlapping fields keyed to different spells of the same level. The only restriction stated is that "If 2 or more fields share an overlapping area, each field has an equal chance of absorbing a spell effect in that area." So you click your rod until one of the fields activates; it casts its level X spell, which conveniently is enough to activate the other field, which casts its level X spell, which activates the first field...

Instant casting of two (instantaneous) spells an infinite number of times.


edit: Another one? Okay, but this one may not be as clear cut. Find a way to repeatedly and infinitely activate an ETF - self resetting trap works, for instance. Make sure you created your ETF under a tree. Get an Acorn of Far Travel from that tree. From the description of ETF: "Spells that require will target the living creature nearest to the field." From the Acorn: "As long as you carry the acorn [...] you are considered to be standing under that oak tree's canopy." Consequently, you're considered to be standing under an oak and that oak is in the middle of the ETF. Likely there's nobody closer than that. So for instance, if you keyed your ETF to a Heal spell... you'd be getting free, automatic Heals all the time, wherever you are.
But the ETF absorbs the spell effect, so the would sit their infinitely charging each other, but you would never see the spell do anything. It says "Effects that are absorbed give no indication of where they went, they simply vanish".

[Chronos]

Oh, good lord... It even specifically calls out the Immovable Rod as an example in the description. What, if anything, were they thinking!?

[Mystify]

Oh, good lord... It even specifically calls out the Immovable Rod as an example in the description. What, if anything, were they thinking!?

They were thinking that it would be used for a trap. The players get to the enemies lair, try to cast a spell, and nothing. They try to use an item, nothing. Suddenly, there is a summoned demon in their face. Or somebody just went bind. If you look at the examples of "typical spells" cast into it, it is pretty clear they are generally retaliatory. Oh, you cast a 6th level spell? Eat 2 fireballs to the face. If used in that capacity, as intended, it is a cool and interesting spell with lots of interesting applications. Its also abusable as hell.

[Lord Il Palazzo]

I guess they were thinking it would make a neat magic trap. (The wizard tries to Knock open a dungeon door. It doesn't work. Puzzled, he tries again and all of a sudden, Summon Monster/Contageon/Blindness/Deafness goes off instead.) It's a pretty cool idea.

That said, it's so blindingly obvious how easy it is to abuse, I'm shocked Wizards didn't notice it. How could you not see the utility, even if you were "only" using the suggested Immovable Rod (or even a cheap, low level wand) to charge the field?'

EDIT: Mystify beat me to it, so pretty much "What he said".

[ILM]

But the ETF absorbs the spell effect, so the would sit their infinitely charging each other, but you would never see the spell do anything. It says "Effects that are absorbed give no indication of where they went, they simply vanish".
And here I was thinking I was so smart :smallfrown:.

[Lapak]

They were thinking that it would be used for a trap. The players get to the enemies lair, try to cast a spell, and nothing. They try to use an item, nothing. Suddenly, there is a summoned demon in their face. Or somebody just went bind. If you look at the examples of "typical spells" cast into it, it is pretty clear they are generally retaliatory. Oh, you cast a 6th level spell? Eat 2 fireballs to the face. If used in that capacity, as intended, it is a cool and interesting spell with lots of interesting applications. Its also abusable as hell.There are so many ways that they could have accomplished this without breaking it. Or even changes that could be made to this spell to salvage it.

- Limiting to one Field per caster, like Contingency, would be a start.
- Giving the spell a duration would be a good idea.
- Giving the spell an upper limit on how many times it would discharge would be really keen; as a start, maybe (10-stored spell level) discharges before the field evaporates.

Just off the top of my head, those three things would go a long way.

[STsinderman]

I must say, this is awesome! And sure to annoy the gm at my next 3.5 session.

[Chronos]

They could also have explicitly forbidden harmless spells from being used with it.

[Cruiser1]

Once again, wizards takes a neat concept, and does not think its consequences through properly.
For an even bigger potential abuse, the text for Energy Transformation Field doesn't say how the linked spell is associated with it. The original post suggests the second spell is presumably cast into it at the same time the field is cast (similar to Contingency) as that's the only thing that makes sense. However it doesn't actually say, so cheesy RAW suggests you just mentally declare what the attached spell is. That can be a spell you aren't high enough level to cast yet, a spell with dozens of metamagic feats you don't have, a spell on another class's list, or even an epic spell by a non-epic character!

Make sure you created your ETF under a tree. Get an Acorn of Far Travel from that tree. From the description of ETF: "Spells that require will target the living creature nearest to the field." From the Acorn: "As long as you carry the acorn [...] you are considered to be standing under that oak tree's canopy." Consequently, you're considered to be standing under an oak and that oak is in the middle of the ETF. Likely there's nobody closer than that. So for instance, if you keyed your ETF to a Heal spell... you'd be getting free, automatic Heals all the time, wherever you are.
That's a great idea, and shows how Acorn of Far Travel (http://www.wizards.com/default.asp?x=dnd/fw/20040710a) is another broken spell (and also banned in Test of Spite (http://www.giantitp.com/forums/showthread.php?p=6885277)). The only problem is Acorn of Far Travel only considers you somewhere unspecified "under that oak tree's canopy", while Energy Transformation Field always casts its linked spell at a particular point within the field designated by you when the field is created (so if nobody's there the casting is wasted). I don't see a way to have an Acorn position you at exactly the right point. The solution of course is to trim the tree enough so there's only one square that's still under it, or else put Mass Heal (http://www.d20srd.org/srd/spells/healMass.htm) instead of just single target Heal in the field so the spell is guaranteed to affect you no matter where you virtually are in the field.

They could also have explicitly forbidden harmless spells from being used with it.
I was going to suggest prohibiting Range: Personal spells from being put in a field, but this is an even stronger and better balance. Also, I'd suggest having a caster level check for a spell to be transformed by the field, making a field similar to a counterspell. That allows a high level mage to still have a chance of casting his highest level spells in spite of a field.

[Asheram]

This would be an quite interesting mechanic for an epic setting though. Binding an epic spell to keep a defensive shield up, or a city flying, or even something like the Astronomican (http://warhammer40k.wikia.com/wiki/Astronomican) if we're going to mix settings.

[Acanous]

Well worded, well written, and totally legal by RAW. Excellent thread, Cruiser1.
I'll be sure to invoke this some time or other. If it's listed in a domain somewhere it would be hilarious to use on a Human Domain Wizard with Alacritous Cogitation and Versatile Spellcaster.

Then you could be doing this at level 1.

[Chronos]

The only problem is Acorn of Far Travel only considers you somewhere unspecified "under that oak tree's canopy", while Energy Transformation Field always casts its linked spell at a particular point within the field designated by you when the field is created (so if nobody's there the casting is wasted).Actually, it says that if the spell is targeted, it chooses the closest valid target within the field, and only fails if there's no target in the field at all.

[Cruiser1]

Actually, it says that if the spell is targeted, it chooses the closest valid target within the field, and only fails if there's no target in the field at all.
You're right, which makes fields even more useful. :smallsmile: Actually, it says "spells that require a target will target the living creature nearest to the field". That implies it has the ability to target creatures outside the field!

Hence, yet another cheesy trick involving the spell is attach Disintegrate to a field, and then be a Lich or some other non-living creature while clicking your Immovable Rod over and over (or set up some physical mechanical device like a water wheel to click the Rod over and over for you). Then cackle in glee as the nearest city erupts in terror as people keep getting Disintegrated every few seconds from an unknown source! :smallamused:

Presumably such targetting should be limited by the range of the spell measured from the designated point in the middle of the field, which prevents using Disintegrate in this way. However, you can definitely use a spell such as Demand (http://www.d20srd.org/srd/spells/demand.htm) which targets "One Creature" with no range limitation. Simply command people to move away as fast as they can go. A few seconds later, the next nearest person will get targeted. A great way to clear out a continually expanding radius around your lair. :smallbiggrin:

[Necroticplague]

Actually, I kinda like the idea of ETF+ Acron of far travel, though it could get abusive easily.

[TuggyNE]

Hence, yet another cheesy trick involving the spell is attach Disintegrate to a field, and then be a Lich or some other non-living creature while clicking your Immovable Rod over and over (or set up some physical mechanical device like a water wheel to click the Rod over and over for you). Then cackle in glee as the nearest city erupts in terror as people keep getting Disintegrated every few seconds from an unknown source! :smallamused:

Disintegrate works on undead and constructs, since it works on objects. Just felt I'd mention that. Other than that, yeah, it's pretty crazy. (Maybe try Finger of Death?)


Actually, I kinda like the idea of ETF+ Acron of far travel, though it could get abusive easily.

Don't you mean "though it is ridiculously abusive in its very essence"? :smalltongue::smallamused:

[Necroticplague]

Don't you mean "though it is ridiculously abusive in its very essence"? :smalltongue::smallamused:

Meh, it's no different from having a spell clock that casts whoever is currently possessing it with buff/heal X, down to the part where it can be stolen (someone can take your buff by swiping the spell clock, someone can take your buff by stealing your acorn). Heck, arguably the spell clock is more useful, since you only have to worry about the item, not just the item and a location (once you cast silence on the spell clock so it can't be heard).

[Namfuak]

Here's an idea. Cast the ETF in a bag of Holding with 3 Magic Missile traps that has Melf's Unicorn Arrow imbued. Go up to a random kid on the street and tell him that there is candy in the bag and he can have some. He reaches in, activates the trap, and suddenly gets bull rushed by 3 unicorns.

[TuggyNE]

Meh, it's no different from having a spell clock that casts whoever is currently possessing it with buff/heal X, down to the part where it can be stolen (someone can take your buff by swiping the spell clock, someone can take your buff by stealing your acorn). Heck, arguably the spell clock is more useful, since you only have to worry about the item, not just the item and a location (once you cast silence on the spell clock so it can't be heard).

I see you are already familiar with the next example I was about to bring up! :smallbiggrin:

But yeah, fair point.

[TroubleBrewing]

Here's an idea. Cast the ETF in a bag of Holding with 3 Magic Missile traps that has Melf's Unicorn Arrow imbued. Go up to a random kid on the street and tell him that there is candy in the bag and he can have some. He reaches in, activates the trap, and suddenly gets bull rushed by 3 unicorns.

This deserves an internet.

Well done! I haven't had to clean ramen noodles off my computer screen since 2011.

[Campbellk8105]

I'm curious, what level spell would you think it'd have to be to change energy transformation field to an emanation like anti-magic field?

My thought, is if you're Epic and you pick up permanent emanation, you can start and stop you're mobile ETF as a free action.

Another question, is how would it work if you had both an anti-magic field and an ETF emanating from you at the same time, given that you make a spell that changes ETF to an emanation.

[Piggy Knowles]

Energy Transformation Field is an area spell. Use Arcane Archer's Imbue Arrow to cast it as a standard action.

[Chronos]

Disintegrate works on undead and constructs, since it works on objects. Just felt I'd mention that. Other than that, yeah, it's pretty crazy. (Maybe try Finger of Death?)By itself, yes, disintegrate works on undead, but Energy Transformation Field says "nearest living creature".

[Slipperychicken]

Energy Transformation Field is an area spell. Use Arcane Archer's Imbue Arrow to cast it as a standard action.

or Uncanny Forethought to cast it as a Full-round.

[PlzBreakMyCmpAn]

Most of this is the usual "i has universe-creation level powerz" that place TO tricks along side their almost as imbalanced as epic spell casting cousins (9th level spells). However I have a thread about to start in min/max it! that uses this spell, which makes me very familiar with this spell. Your last paragraph about the ability to use it for its originally desired anti caster purposes is the most useful part of the OP. I'll address the rest:

First of all, "if it has enough stored spell levels and the duration of its previous casting has expired." So each of those shapechanges now have costly components. Even if you made a bunch, someone would have to move the focus around, which would be in the right of a DM call to un-proc the linked spell. So no gains there.

Oh and those shapechanges aren't persisted. No where does it say metamagic can be applied to the linked spell. That's the RAW. The RAI clearly indicates that this spell can't produce high level effects in the last paragraph. Since limited wish a 7th level effect beats this spell which is a 7th level effect then presumably only 0-6 level spells are fair game. In between is the question of whether or not spells you don't know can be 'linked' by the caster. See Linked Power and persistent spell for similar examples.

Also extradimensional spaces aren't a good idea because "spell that require a target will target the living creature nearest to the field" and DnD has funny cosmology. Best keep it all 100% on the material plane.

The 'a minute or so' to auto reset traps essentially means you have to count on it taking 2 minutes each. That makes what 9*6*2=72 burning hands traps or 36k for proc'ing a 9th level plus the 5k for a casting means ... wait if you are allowing no-action-required magical trap crafting then this is all moot. 12kgp and less than 1kxp for mage armor forever with no other costs? And that's without straight-forward CL shenanigans. Its persistent spells via cheap gp instead of difficult to procure DMM turning uses. Any DM that allows PCs to craft traps is asking for it. It's clearly TO.

So where does that leave us? Clicking rods to turn save 1-6 level spell slots? A 7th level generating 1-6 level effects isn't new. This one is just an expensive way to do it more effectively over the long run. Yes its powerful if for some reason you need to use your low level spell slots on something else and have WBL to blow ... but a lot of things fit that description. In short this is the price a DM pays for allowing the top third tier of spells (since the middle 4-6 already breaks the game in cor

[flabort]

If you aren't living, and keep these in bags of holding, you can prepare all blasty spells, and still be a Batman Wizard. Keep all your utility spells in bags, if you need to grease something, click-click. In fact, you can load up the entire party with thousands of portable ETFs, and give them a few immovable rods. When the situation calls for any spell, click-click.

If you can use metamagic in an ETF, use that one trick that allows you to cast two spells at once, put it in an ETF. Overlap it with another, as per the infinite spells trick that didn't work above. OK, now, it will cast one spell into the other ETF, and one at the nearest living creature. The other, when it gets the one spell, will do the same.
Maybe. I dunno if that metamagic can work that way; the spell that gets absorbed must be equal to the cast one, so you'd probably need some reducers to make it work.
This one actually works, because one spell is an area, and the other is targeted; The area is absorbed, the target is not. The only way it may not work, is if I'm mistaken, and you can't put a 5th and 4th level spell both into a 5th level slot by using reducers.

[Cruiser1]

First of all, "if it has enough stored spell levels and the duration of its previous casting has expired."
Energy Transformation Field not casting a spell if its previous casting is still going on is an important point. Hence you can't give everybody in an army a buff like Shapechange. You can still use fields for self-buffing of course. Fields are still excellent for armies when powering instantaneous duration spells like Heal. Also Time Stop, so clicking over and over to give yourself an hour long Time Stop works. Interestingly, that's a case where errata for Time Stop to be instantaneous duration (so you can't cheesily persist it for an all day Time Stop) is a benefit to the optimizer, because you can stack it over and over from a field, without having to ready an action to cast it again each moment the current Time Stop ends. If you want to give everybody in an army a powerful buff with duration, you need to use a resetting magic trap, which is slightly more expensive.

The 'a minute or so' to auto reset traps essentially means you have to count on it taking 2 minutes each.

Automatic
The trap resets itself, either immediately or after a timed interval.
Automatic reset traps (http://www.d20srd.org/srd/traps.htm#automatic) can immediately reset (or reset after a timed interval if you prefer). Simply choose for your autoreset magic trap to reset immediately, when crafting it or paying someone to craft it for you. The part about "resetting a trap usually takes only a minute or so" is in the section Repairing And Resetting Mechanical Traps (http://www.d20srd.org/srd/traps.htm#repairingAndResettingMechanicalTraps) and only refers to those lesser non-magic traps.

Any DM that allows PCs to craft traps is asking for it.
Indeed! After all, abuse of immediately autoresetting magic traps are one of the key features of the Tippyverse (http://www.giantitp.com/forums/showthread.php?t=222007).

Oh and those shapechanges aren't persisted. No where does it say metamagic can be applied to the linked spell. The RAI clearly indicates that this spell can't produce high level effects in the last paragraph. Since limited wish a 7th level effect beats this spell which is a 7th level effect then presumably only 0-6 level spells are fair game. In between is the question of whether or not spells you don't know can be 'linked' by the caster.
There's nothing that says metamagic spells can't be put inside Energy Transformation Field either, or any other limits on the attached spell (such as it can't be Range: Personal, or has to be a spell that you can actually cast) which is of course the problem (or the opportunity for the optimizer. :smallwink:) Ruling that Energy Transformation Field can't power spells over 6th level is one way to help reduce abuse, but I don't see that as RAI. When there are limits on spell levels, they're explicitly stated, such as Contingency (http://www.d20srd.org/srd/spells/contingency.htm) only allowing spells up to 6th level, or wands only allowing spells up to 4th level. There are lots of examples of lower level spells "beating" higher level spells, such as Dispel Magic (3rd) can remove Shapechange (9th) if you roll well on your dispel check. Because allowing spells you can't even cast leads to ridiculous cheese such as a 13th level Wizard casting Energy Transformation Field and attaching an epic spell to it, what I see as a reasonable interpretation for this poorly written spell is that you have to cast the attached spell at the same time as Energy Transformation Field (see Contingency (http://www.d20srd.org/srd/spells/contingency.htm) again for an example). That means you can attach a metamagic version of a spell, provided you have the metamagic feat, and provided you have a high enough slot to cover the metamagic spell (so to attach a Persistent 9th level spell requires very high level slots or a bunch of metamagic reduction).

Also extradimensional spaces aren't a good idea because "spell that require a target will target the living creature nearest to the field" and DnD has funny cosmology.
Extradimensional spaces aren't any different from the material or any other plane with respect to how Energy Transformation Field is being used. When you cast a field inside of a Bag of Holding, you reach inside the bag so you're arm is over the designated spot where the attached spell is cast. That means the attached buff will always be cast on your arm (since it's zero distance away) and hence upon you. If you want to, you can completely climb inside the Bag of Holding (even a Bag of Holding I forms an internal space over 3 feet on a side, easily enough for a Medium creature to fit into) but that shouldn't be necessary.

[Grinner]

You know, I'm start to see the appeal of being a rules lawyer...

[Tedective]

Rary's Arcane Conversion.
Heighten Spell.
Easy Metamagic: Heighten Spell.

[Jormengand]

Polymorphing into a garbler so you auto-succeed your truespeak checks and then heightening any utterance you like to CL infinite will actually get you infinite spells, and do so right now this instant.

[DarkWhisper]

http://forums.crackberry.com/attachments/news-rumors-f40/179809d1373210666t-apple-going-down-billions-tax-fraud-thread-necromancy.png