Does being lifted 10 feet into the air and then dropped count as "moving into or within the area" of Spike Growth?

Question

Let's say that an enemy creature is standing in the center of the area of effect of the Spike Growth spell, which states:

The ground in a 20-foot radius centered on a point within range twists and sprouts hard spikes and thorns. [...] When a creature moves into or within the area, it takes 2d4 piercing damage for every 5 feet it travels.

If another creature lifts the creature up ten feet and then drops them (perhaps by flying above the enemy and casting Thorn Whip), does the dropped creature take any of the piercing damage described in the Spike Growth spell? If so, how much damage?

To put it another way, does leaving the ground and then being dropped onto the ground count as moving out of (and then into) or moving within the area of Spike Growth, given that the area is "the ground in a 20-foot radius"?

This is not a question about willing vs. unwilling movement. My question would still stand if the creature had a fly speed and used it to willingly fly up 10 feet and then willingly fall or land. This is about verticality, not voluntarism.

Answer 1

Yes, falling into spike growth counts.

There are two parts to this question that we need to check, and the first is simple. Does falling count as moving into the area? This seems pretty plainly to me to be the case: you go from not being in the area (“the ground in a 20-foot radius”) to being in the area (“the ground in a 20-foot radius”), and you didn’t get there via teleportation.

The other part is whether or not spike growth requires willing movement, or if any sort of forced movement will do. This is addressed in this Q&A, Spike growth with forced movement, and I will reproduce the relevant portion of my answer to that question:

Notably, spike growth does not require willing movement:

When a creature moves into or within the area, it takes 2d4 piercing damage for every 5 feet it travels.

It only requires that a creature move within the area, the method and intent of movement are not relevant.

In contrast, the rules use the concept of “willing movement” to specify when movement must be of the creature’s own volition to trigger some feature. For example, the cantrip booming blade reads:

If the target willingly moves 5 feet or more before then, the target takes 1d8 thunder damage, and the spell ends.

Shoving a creature under the effect of booming blade will not trigger this effect, since such movement is not willing movement.

We see a similar distinction made in the rules for opportunity attacks, where it is specified that only moving that uses your available movement, action, or reaction trigger the opportunity attack.

So in the absence of any sort of qualifier in the description of spike growth, any sort of movement into or within the area of spike growth will trigger its effect, be it shoving, dragging, magical pushing, or even falling.

So bringing it all together, leaving the area (“the ground in a 20-foot radius”) does not count as moving into or within the area, but falling into the area (“ the ground in a 20-foot radius”) does, so they would take 2d4 damage for their initial entry into the area.

Answer 2

Being dropped is not movement, but check with your DM

Movement is a defined term for creatures (p. 190, PHB)

On your turn, you can move a distance up to your speed. You can use as much or as little of your speed as you like on your turn, following the rules here. Your movement can include jumping, climbing, and swimming.

If the creature is not spending any of its speed, it is not moving. It maybe is being moved, e.g. from the effect of a thunderwave spell, or by thorn whip, but being moved is not moving. These spells also do not say they move the creature, thorn whip says "you pull the creature closer", thunderwave says it the creature is "pushed (...) away". This is similar to teleporting into the spike growth area, which also is not moving.

The rules for opportunity attacks also support the idea that only active movement by spending speed counts as moving for effects that harm the creature:

You can make an opportunity attack when a hostile creature that you can see moves out of your reach. [...] You also don’t provoke an opportunity attack when you teleport or when someone or something moves you without using your movement, action, or reaction, For example, you don’t provoke an opportunity attack if an explosion hurls you out of a foe’s reach or if gravity causes you to fall past an enemy.

Therefore, the creature takes no damage from spike growth when being dragged around or pushed around by these spells.

Counterarguments

There are two spells that could be used to argue that falling counts as moving, and that the stone spike talks about moving not in the game term sense, but in the more general, common-language sense of the word that means changing your position.

The first is Booming Blade, which demands that a creature moves willingly to suffer its effect. As you only can spend speed when you willingly do so, that addition would be unneccesary if to move always meant spending speed. However, this spell was published much later, and it is possible that the willingly was added to make it easier for readers to understand the intent.

The second is Antipathy/Sympathy, which says

he creature must succeed on a Wisdom saving throw or use its movement on each of its turns to enter the area or move within reach of the target

Again, if moving always would require movment, then stating the creature must use its movement to do so would be superfluous. Again, this is not clear cut, because the creature might also have other, better ways to get closer to the target, like teleporting to it, and maybe the text is there to make it clear so the spell does not force it to do this.

Lastly there is also the narrative perspective. While technically, spells only do what they say they do, some DMs consider what makes sense from a narrative perspective. If there is an area full of sharp spikes, being dropped onto them would make sense to cause damage.

So check with your DM, if they allow you to deal damage, or not.

Answer 3

RAW: No damage, but DM has to decide for RAI

First, DnD5e has no rule mechanics (that I know of) for dealing with vertical movements. Almost every situation is handled as if the world is a 2D surface (although not flat). The described situation is clearly outside of this 2D-world thinking.

Second, there are no rules in the spell description regarding falling into the Spike Growth area.

So, one could conclude that falling into this area is not a kind of damage inflicting movement, because of the 'no hidden rules' agenda.

Following this, I would think: RAW there is no damage at all. Still, it could be worth to trap the victim inside the Spike Growth area.

But, as you can read in the discussion between Thomas and Nobody, it's not that clear that falling is not moving/movement.

RAI: The way the spell is described and following our rational understanding of the physical world work, I think, everyone would agree that falling into the Spike Growth area should inflict damage: There is no real difference between moving lateral through or vertical into the Spike Growth area, although moving vertical is limited by the ground itself of course.

So I think, that the DM in your game really has to decide, because there are no clear rules at the moment. I would decide to follow the RAI answer.

Regarding the actual inflicted damage, let's have a look at some rules (DMG, section traps, p. 122f):

Spiked Pit. This pit trap is a simple, hidden, or locking pit trap with sharpened wooden or iron spikes at the bottom. A creature falling into the pit takes 11 (2d10) piercing damage from the spikes, in addition to any falling damage.

So, here the falling damage is clearly differentiated from the spike damage. A spike in such a pit trap is likely to be similar to a spear head. Notice that this trap damage is much more than a regular hit from a spear. But the spikes from the Spike Growth spell are smaller, I would reason, because these are camouflaged:

The transformaton of the ground is camoufaged to look natural. Any creature that can’t see the area at the tme the spell is cast must make a Wisdom (Percepton) check against your spell save DC to recognize the terrain as hazardous before entering it.

I, for myself, would assume double (or even triple) base damage, so 4d4 (or 6d4), which can be halved with an successful Dex(Acrobatic) saving throw. And I tend to give Disadvantage to this saving throw because a) the spikes are camouflaged (which makes it more difficult to avoid the spikes) and b) it's quite difficult to change the 'landing spot'. Plus, the damage for falling 10 ft; 1d6.

Last note: This spell causes continuously damage as it says 'for every 5 feet'. Also, it does not contain any wording like "if entered for the first time in a turn" (like in some other spells). So, if somehow the victim can be raised into the air and dropped several times in a turn the damage should be applied for each 'landing'.