Spike Growth and Verticality

[Segev]

How high above the surface on which spike growth is cast must a creature be moving to avoid the damage? Is jumping over it enough? What about swimming, if it is cast on the bottom of, say, a three- to five-foot-deep pool or river?

Is using spider climb to walk on the ceiling overhead enough to avoid it?

If someone walking on the 10-foot-high ceiling (perhaps with slippers of spider climbing) who is standing above the sPike growth AoE uses thorn whip to drag a target also standing in the spike growth AoE ten feet towards him, is the target dragged through the spikes, or is he dragged above them sufficiently to avoid the damage for moving through them?

[stoutstien]

Due to it's semi camouflaged nature and specifically calls out ground (unlike plant growth) id say it's pretty low profile. I would allow it be cast sideways on walls and such
Id rule that pulling someone straight up wouldn't trigger the move damage unless they were prone but falling back would.

[Skrum]

At the table I play at, we take the flavortext of the spell pretty literally. It's spikes on the ground, so jumping over the spikes is legit. I think we apply damage as the space is left though? So if someone is standing in a spiked growth area, and they jump out, they'd still take the damage for the square they left.

Climbing along the wall or ceiling over an area affected by the spell would absolutely avoid the damage. Getting pulled into the spikes....I would rule that it does damage, for sure.

My general feeling would be to apply the damage for leaving AND entering the space, but not both for the same square. So if a character starts their turn in a space with spiked growth, and they leave the square using any method aside from teleportation, they take damage. If it's not their turn and they get moved into a square with spiked growth, they take damage.

[da newt]

In my head cannon the spikes are short - like 6" dagger blades of grass. Nasty for sure, but short.

[Greywander]

The spell text talks about "the ground" and "the area", so my assumption is that the spikes lay flat and any height prevents damage and other effects. Nothing in the spell suggests it affects a volume, just an area, so I think even if you were hovering 0 feet above the ground you would avoid it.

Of course, one would expect spikes to project up from the ground and not lay flat (as that doesn't make much sense), so a reasonable DM would likely add a bit of height to the spell, especially if someone is arguing they can hover 0 feet above the ground so long as they aren't walking on it.

Keep in mind spells like Web specifically fill a volume, and Web even calls out webs layered on the floor as having a depth of 5 feet. 5e isn't really designed with verticality in mind, though. For example, while creatures occupy a space of a specific size, there aren't any rules for the height of a creature's space. I think even technically flying creatures can't occupy the same space as a creature on the ground, as space is treated as completely 2D. Of course, the rules expect you to use some common sense to fill in gaps such as this, so I don't know I'd say that it's RAW that flying creatures can't occupy the same space as creatures on the ground. More like the rules don't cover it, as flight is obviously an exception to many rules written with non-flying creatures in mind.

[Dork_Forge]

I play on a grid, so I would say the entire 5ft square spikegrowth is touching must be avoided, so in the 10 ft on the ceiling version, the person on the ceiling would be out of the aoe.

[Slipjig]

Since the spell specifically requires a Perception check to recognize the ground as hazardous and doesn't block LOS, I'd say it's probably only a few inches high at most.

[PhoenixPhyre]

Since the spell specifically requires a Perception check to recognize the ground as hazardous and doesn't block LOS, I'd say it's probably only a few inches high at most.

Yeah. It's an area effect, not a volumetric effect. Effectively the ground is covered with legos or d4s (ie caltrops, but nastier). Any non-trivial flight will clear it (ie creatures that are using a fly speed to move), as will a jump (assuming both starting and ending locations are clear of the area). I'd say jumping from within the area means one hit, as would jumping to another place within the effect. But I'd look severe askance at people who failed the Perception check and then started bunny-hopping.

[Segev]

Yeah. It's an area effect, not a volumetric effect. Effectively the ground is covered with legos or d4s (ie caltrops, but nastier). Any non-trivial flight will clear it (ie creatures that are using a fly speed to move), as will a jump (assuming both starting and ending locations are clear of the area). I'd say jumping from within the area means one hit, as would jumping to another place within the effect. But I'd look severe askance at people who failed the Perception check and then started bunny-hopping.

I might forgive the bunny-hopping after they took a couple of instances of damage, especially if they keep doing it even outside the area. "Okay, ground pointy; minimize contact!"

[PhoenixPhyre]

I might forgive the bunny-hopping after they took a couple of instances of damage, especially if they keep doing it even outside the area. "Okay, ground pointy; minimize contact!"

Yeah. Afterward? Not a big deal. Just based on meta stuff (like the VTT having an AoE on that area or it printing that Spike Growth was cast? No bueno.

[stoutstien]

Yeah. Afterward? Not a big deal. Just based on meta stuff (like the VTT having an AoE on that area or it printing that Spike Growth was cast? No bueno.

Bonus Q: if you ready action to cast thorn whip on a jumping enemies trying to get out of spike growth can you cancel the jump and make them fall back in place?

[Segev]

Bonus Q: if you ready action to cast thorn whip on a jumping enemies trying to get out of spike growth can you cancel the jump and make them fall back in place?

I don't know about cancelling the jump, but you would theoretically move them 10 feet towards you before they jumped.

Where these questions really start to matter is in trying to determine how much higher you can be than the target when using thorn whip and still manage to force him to go through two squares of spike growth, rather than pulling him up and over it. As long as you can justify the "arc" of pulling him ten feet up at an angle as making him land 10 feet away, though, if we use the "eitehr entering or exiting, but not both" rule of thumb, you can probably get both five foot increments' worth of damage out of pulling him from anywhere that is horizontally more than ten feet away. Judging how close you have to be, horizontally, to have him within 30 feet in Euclidean distance is a matter of calculating hypotenuses.

[sithlordnergal]

I'm in the "it fills the 5ft cube on the ground" category of thinking. So if you can move 6ft above it, you're fine. It also means you can't really jump over/through it unless you have a vertical jump of 6ft or more. I figure that's a pretty fair way to run it, since it can't be ignored without a fly speed, or some really heavy investment in your vertical jump ability.

As for why you might not notice it? Meh, its magic. Might be camouflaged despite filling that 5ft area.

[PhoenixPhyre]

Bonus Q: if you ready action to cast thorn whip on a jumping enemies trying to get out of spike growth can you cancel the jump and make them fall back in place?


I don't know about cancelling the jump, but you would theoretically move them 10 feet towards you before they jumped.

Where these questions really start to matter is in trying to determine how much higher you can be than the target when using thorn whip and still manage to force him to go through two squares of spike growth, rather than pulling him up and over it. As long as you can justify the "arc" of pulling him ten feet up at an angle as making him land 10 feet away, though, if we use the "eitehr entering or exiting, but not both" rule of thumb, you can probably get both five foot increments' worth of damage out of pulling him from anywhere that is horizontally more than ten feet away. Judging how close you have to be, horizontally, to have him within 30 feet in Euclidean distance is a matter of calculating hypotenuses.

Readied actions, for me, trigger completely after the trigger resolves. Jumps are atomic enough that your thorn whip will trigger after they land. At most generous, you'd trigger it when they're up in the air, having moved (horizontally) 5'. And depending on the relative vectors, you'd pull them anywhere from 5' behind where they started (triggering damage if that's in the zone, for the diametrically opposed vectors case) to pulling them another 10' forward (triggering damage if that's in the zone for the parallel vectors case). Either way, if they land in the zone, they take damage.

@Segev--I've given up on doing Euclidian distance whatsoever. Don't care if it means the spacial metric is kinda odd. Way too much effort. D(x0, x1) = ABS(MAX(x1-x0, y1-y0)), not SQRT((x1-x0)^2 + (y1-y0)^2).

[Segev]

@Segev--I've given up on doing Euclidian distance whatsoever. Don't care if it means the spacial metric is kinda odd. Way too much effort. D(x0, x1) = ABS(MAX(x1-x0, y1-y0)), not SQRT((x1-x0)^2 + (y1-y0)^2).

If I find the math too hard, I tend to pull out a tape measure and just angle it. We play on inch grids, so the ruler translates easily enough. I understand that might be more effort, still, than you want to put into it, but it works out well for me.

[Chronos]

If you want a metric that's a decent approximation of Euclidean, but still easy to calculate, take the X and Y distances, halve the smaller one, and add them together. This is often used in games (both tabletop and computer), and was in fact the default rule in 3rd edition (it's the same effect as "diagonals cost 1.5 times normal movement").

As for jumping, when you take off or land, you're pushing against the floor extra hard, which seems like a bad idea. I'd rule that jumping around within the spiked area does the same damage as just walking.

[Segev]

As I've been thinking about this, something occurred to me: the spell says that the fact that the area is trapped is hidden from those who don't see it placed. It says nothing about the fact that it's difficult terrain, so it's possible that that is obvious even to those who did not see it placed. It does, however, imply that the trapped nature is obvious to those who saw it placed, though that could just be a consequence of "wait, that difficult terrain jutted up spikily like magic; it's probably dangerous."

That said, since it is "spike growth," and not "flat ground, hidden caltrops," I wonder if a reasonable interpretation is that the area of the spell has the ground have obvious large, at least vaguely conical rocks with fractal-like juts from them. Spikes, if you will, with maybe more spikes growing on them, and perhaps further spikes on those. This makes the ground uneven in apparent height, and thrusts spikes into the air off of said ground to varying heights (perhaps capping out at 5 feet above the base level of the ground). The fact that razor-sharp snags and jags are unavoidably everywhere is what's hard to see; creatures know they will have to pick their way through it due to the uneven and obstructed nature of the terrain, but don't realize they'll inevitably lacerate themselves on the stones until they're already in there.

This would give height to it, though we have to assign that height (which I have suggested might be five feet).

[ChaosStar]

I had always thought it made barbed wire grade brambles. Guess that's what I get for not reading spells closely.

[Greywander]

How high above the surface on which spike growth is cast must a creature be moving to avoid the damage? Is jumping over it enough? What about swimming, if it is cast on the bottom of, say, a three- to five-foot-deep pool or river?

Is using spider climb to walk on the ceiling overhead enough to avoid it?
Circling back to the OP, I'd say the height is ambiguous, but any amount of height would be enough to avoid it. As I said previously, even hovering 0 feet over the ground would likely be sufficient, so long as you're not walking through it. I say this under the assumption that if a certain amount of height is required, achieving said height would be trivial and should be taken for granted. If you have a fly speed, you're not going to fly so close to the ground to drag your feet through spikes. It's simply not worth the effort of including the change in height in the movement calculations. Same applies to swimming; Spike Growth cast on the bottom of a body of water would only affect those choosing to walk along the bottom. Edit: the water might need to be a certain depth to swim through it, so a 3-foot depth would probably be too shallow for medium creatures, but maybe not for small or tiny.

Jumping should be fine so long as you can completely clear the affected area. Jumping out of or into the affected area is more iffy; you should definitely take some damage, and jumping into a thorn bush is probably more painful than walking into it. Again, it's a question of if it's worth the bother to track it. The simplest option is to either treat jumping out of or into Spike Growth as 5 feet of movement through the spikes, or to ignore jumping and take full damage the same as if you walked through it, unless you can clear the area completely in one jump.


If someone walking on the 10-foot-high ceiling (perhaps with slippers of spider climbing) who is standing above the sPike growth AoE uses thorn whip to drag a target also standing in the spike growth AoE ten feet towards him, is the target dragged through the spikes, or is he dragged above them sufficiently to avoid the damage for moving through them?
Thorn Whip should pull them straight towards you, in which case they'd gain immediate height, then fall down. That said, it makes sense that gravity could hold them on the ground, allowing you to drag them through the spikes. RAW, I think they'd avoid the damage, but I think a reasonable DM would allow them to take damage. I'd just caution you that it's only fair if NPCs can use the same tactics against you.

In general, I think that's the best compromise for a lot of "does this work?" type of rules questions: If it works, then enemies can use it against you. With that in mind, do you still want it to work? It's not hard to come up with a justification either way, so it's really just a question of which will be more fun for that table. As such, I think it makes sense for the DM to offer this compromise and let the players decide which way they want to go.

[Chronos]

"Do you want the enemies to be able to do this?" isn't a bad standard in general, but it's less applicable here, because very few enemies have the ability to cast Spike Growth. Most enemy spellcasters will either cast from the wizard or cleric list (neither of which includes this spell), or have a set list of spells they can cast (which doesn't usually include Spike Growth). Very few enemies in the books cast spells drawn from the druid list, and even fewer from the ranger list, whereas PC rangers and druids aren't all that rare.