Can cows that I conjure using the conjure animals spell fall onto targets, thereby dealing damage?
The feys summoned by conjure animals take the shape of a beast (a cow, in this case). But since the feys are spirits, would they do any damage if they fell on an enemy?
Related question: If a creature is dropped on a monster, how much damage does each of them take?
With the Conjure Animals spell, you can definitely try this!
You summon fey spirits that take the form of beasts and appear in unoccupied spaces that you can see within range. Choose one of the following options for what appears:
- [...]
- Eight beasts of challenge rating 1/4 or lower
So you refer to your DM that you wish to summon 8 CR 1/4 beasts, and let's assume he is a large dairy fan, and gives you 8 cows.
You then pick "unoccupied spaces that you can see within range", which is 60 feet. Let's say you put one 50 feet above your target, and the others you ignore. Once the spell is cast, the cow will fall down 50 feet on top of your enemy, taking 5d6 bludgeoning damage from the fall.
Now, the question is whether this damage is dealt to the enemy. This question offers all the guidance we need, if you use the optional rule for falling onto a creature from TCE (p. 170):
If a creature falls into the space of a second creature and neither of them is Tiny, the second creature must succeed on a DC 15 Dexterity saving throw or be impacted by the falling creature, and any damage resulting from the fall is divided evenly between them. The impacted creature is also knocked prone, unless it is two or more sizes larger than the falling creature.
So your enemy must succeed on a Dex save, and if he fails, the fall damage would be divided between both of them, and the enemy would fall prone.
If you want all your cows to hit the same enemy, it's a bit more complicated. You'd need some sort of conga-line of falling cows. To save your DM's sanity, I'd stick to 1 cow per enemy.
It's great for bursting damage if you have enough height and really need it. You can basically create 8 areas that will take around 2d6~3d6 bludgeoning damage. But usually, it will be better to have 8 beasts for an hour, soaking damage, and doing 7 damage per hit (or more if they charge).
Hilarious idea anyway.
The basic issue in the base rules is this: Conjure Animals describes how the caster summons animals at a given point in space. You can pick a point in the air, sure, so so far, so good. But the spell does not say anything about making an attack, which is where we run into a problem.
Attacks generally have details which simulate the attacking character trying to hit their target in a meaningful way and with a chance of failure, such as rolling a d20 and adding the appropriate attack modifiers to try to beat the target's AC. Some attacks are presumed to hit, but give the target an opportunity to avoid damage, such as making a saving throw. Some attacks always hit their targets, like Magic Missile.
The problem with the meat-eor plan is that the spell doesn't involve any of those things. There is no method for how you would determine if the cow is appropriately placed when summoned-- there is no attack roll, and so there is nothing to compare to the target's AC. There is no presumption of automatically hitting with a chance for the target to make a saving throw.
So the weight of the cow is a non-issue. Even though the plan would have some chance of working in real life (with a few modifications to what constitutes "real"), the game rules don't provide any way to figure out if this would hit a target. And this is before trying to figure out how much damage should be dealt by having a large object fall on a target without having any damage dice assigned to it.
So, the base rules as written do not permit this. The spell doesn't work that way, and none of the elements of the plan are defined in game-mechanical ways that allow us to reliably determine any of the plan's outcomes. That said, if you work with your DM to figure out mechanics for it, then you can do it. There is guidance in a supplement, detailed below, if your DM is inclined to allow it.
Tasha's Cauldron of Everything does, in fact, offer a way to determine if a target is hit and damaged by another creature falling onto it from above. It's up to your DM if this optional rule is used, but it does offer a way to adjudicate this in the way you're hoping. The optional rule for falling onto a creature states (TCoE, p. 170; "Chapter 4: Dungeon Master's Tools"):
If a creature falls into the space of a second creature and neither of them is Tiny, the second creature must succeed on a DC 15 Dexterity saving throw or be impacted by the falling creature, and any damage resulting from the fall is divided evenly between them. The impacted creature is also knocked prone, unless it is two or more sizes larger than the falling creature.
The maximum damage you can expect is unrelated to the conjured animal's weight. The conjured animal suffers 1d6 damage per 10 feet it falls, so if the caster conjures the cow directly above itself at the spell's maximum range (60 feet) the cow can accrue 6d6 damage dice. This translates to a potential maximum of 3d6 damage dice for the creature struck by the cow.
3d6 damage is relatively underpowered for a 3rd-level spell slot, so there shouldn't be any concerns about balance.
As spelled out in the Sage Advice Compendium, the designers' intent for Conjure Animals is that the spellcaster would choose one of the options from the bulleted list for the spell (i.e. the number and CR of creatures that appear), and then the DM decides exactly which creatures appear. If you ask for eight CR 1/4 animals to appear 60 feet in the air, you might get Giant Owls, Giant Bats, or Pteranodons.
The conjure animals spell description implies that the conjured animals uses the standard statblock for that creature, with the exception of the creature type (which is now fey). It does not mention any change to creature size, weight, or other feature that might prevent falling damage. So per C. A. Jones's answer to the linked question, the optional rule for Falling onto a Creature from Tasha's Cauldron of Everything (p. 170) should apply:
If a creature falls into the space of a second creature and neither of them is Tiny, the second creature must succeed on a DC 15 Dexterity saving throw or be impacted by the falling creature, and any damage resulting from the fall is divided evenly between them. The impacted creature is also knocked prone, unless it is two or more sizes larger than the falling creature.
However, note the following caveats:
Spells do only what they say they do and nothing else. The spell does not say the creature will hit an opponent if it lands on them. While you could, technically, summon a cow or the like into an empty point in space above an enemy's head, that doesn't mean that the falling creature will hit or even damage them.
The rules for hiding state that combatants are always watching their surroundings:
In combat, most creatures stay alert for signs of danger all around
So they will be able to spot a cow dropping from above and be able to sidestep it. Even if it lands in the same space, two creatures can occupy the same space during combat - you just can't end your movement in the same space as another creature, so the cow would have to move out presuming it survived the impact.
A DM could call for a Dexterity save to avoid a falling creature, but that would be at their discretion.
