Is there any class, ability or spell to spontaneously activate abilities of others?

[SinsI]

I'm looking for any magic item, class or ability that would allow one to spontaneously activate magic items in possession of others; same for spell-like abilities or memorised spells - with or without ability to control them - turning those abilities against their owners.

If there is no such thing, homebrew would be OK too.

I think that such abilities can be a great way to make life much harder for casters.

[Pit-ik-cha]

The factotum's 19th-level ability allows you to steal 3 extraordinary abilities from base classes/day.

[Der_DWSage]

Offhand, aside from the Factotum, I can only think of the Spellthief and the spell Spell Turning. Being able to steal or turn your action against you is not exactly a common thing in D&D.

For general defense though, there's also the Spellblade item (I think that's what it's called) and a Rod/Ioun Stone of Negation.

[Helluin]

Reciprocal Gyre and Kleidoscopic Doom don't do exactly what you want, but they do turn the active buffs against their owners

Again, Perfect Summoning Field doesn't directly hurt spell casters, but it converts any evil summoning spells cast within it to good summoning spells, and iirc it also makes the summoners incapable of controlling those critters

[SinsI]

Not quite what I wanted.
I want something that would make all the stored "gunpowder" explode into its owner's face, not something to steal or turn their actions against them.
Something along the lines of "you activate your Chaos Aura, and every magic item in its radius has a chance to spontaneously activate". Could be useful in a trap form, too.

Not sure whether the result of that activation should be the actual effect of the spell or some kind of damage instead (since it is botched up).

The latter might make a decent Martial maneuver - you hit the enemy and he loses a few of his highest level spell slots (the way he would from Negative Levels), as well as receives additional bonus damage based on the level of spells lost.

[Extra Anchovies]

For almost every magic item, you need to be in possession of the item to use it, so no dice on that front (unless you know they have an explosive rune bomb on them and intentionally fail to dispel, in which case lots of dice, on all sides).

What purpose do you want these abilities for?

[Kelb_Panthera]

For psionics there's the disease cascade flu.

[SinsI]

What purpose do you want these abilities for?

Qui gladio ferit, gladio perit.

D&D is too reliant on magic items and spells.
Normally, when you think "what hinders spellcasters the most?", the first thing that comes to mind is Anti-Magic Zone - which is not fun at all, since it is a "you can't do anything that you like" kind of thing.

"Spontaneous Activation Zones" can really level the playing field, making mundanes much more relevant.


For almost every magic item, you need to be in possession of the item to use it, so no dice on that front (unless you know they have an explosive rune bomb on them and intentionally fail to dispel, in which case lots of dice, on all sides).
Why should it work on one type of magic item (explosive runes) and not the others (i.e. wand of fireballs)?
Not rules-wise, but gameplay-wise.


For psionics there's the disease cascade flu.
Good! Very close to what I had in mind.

[Kelb_Panthera]

D&D is too reliant on magic items and spells.
Normally, when you think "what hinders spellcasters the most?", the first thing that comes to mind is Anti-Magic Zone - which is not fun at all, since it is a "you can't do anything that you like" kind of thing.

I'm presuming you mean dead magic zones since antimagic fields tend to just get those who employ them killed by high-op spellcasters just that much faster.

Removing magic items is easy enough, you just have to replace the base numbers unless you want to have to be a -lot- more careful in selecting your party's enemies. My go-to is to give all PC's the benefits of Vow of Poverty (Book of Exalted Deeds) without meeting the requirements and use UA's class based AC rule. This allows the PC's to reach the numbers they're supposed to without having to pick up a "christmas tree."

Weakening magic on the whole, however, is a lot more difficult. You can simply ban it; say that there are no spellcasters anywhere in the world and then add back in some spells as rituals ala UA. That's a tad extreme but it works. You could make the incidence of wild-magic zones much more frequent; any spell, or spell effect produced by a magic item, goes weird unless the caster, or item, succeeds on a caster level check.

Be aware, players that prefer casters aren't going to like -any- of this.