The bulette can use its deadly leap ability to jump onto its targets and possibly knock them prone if they fail their saving throw. But having done so it will be sharing the same space as them. The rules state you can't willingly end your turn in the same space as another creature but I can't see a good reason why a bulette would try to move away, assuming it still has movement left.

If the creature is prone, the bulette can occupy the space

From the detailed description we find this specific ability overwriting the general case of movement into another creature's space:

Deadly Leap

If the bulette jumps at least 15 ft. as part of its Movement, it can then use this action to land on its feet in a space that contains one or more other creatures. Each of those creatures must succeed on a DC 16 Strength or Dexterity saving throw (target's choice) or be knocked prone and take 14 (3d6 + 4) bludgeoning damage plus 14 (3d6 + 4) slashing damage. On a successful save, the creature takes only half the damage, isn't knocked prone, and is pushed 5 ft. out of the bulette's space into an unoccupied space of the creature's choice. If no unoccupied space is within range, the creature instead falls prone in the bulette's space. (MM, p. 34)

This looks like a specific case (bulette's special ability) overwriting the general case of the rule about space occupation. At the end of its turn, the bulette ends up occupying the creature's space(s). No limitation on now much movement is used prior to the Deadly Leap is made; so if the last 15' is all that is left, the bulette and its prone targets are in the same space at the end of the bulette's turn. The target area creatures are either prone (under the bulette) or knocked out of the way into an adjacent space (depends on save/no save, space/no space). That ruling holds to "Specific Over General" in a slightly different way that TJL's fine answer. Only proned creatures end up in the same space at the end of the bulette's turn.

What was the bulette trying to do? Kill/harm the target, or knock it out of the way with a special ability that is mechanically like a spell: it requires a save for half damage, and another effect. This is similar to the Thunderwave spell's condition(knocked back) and damage as result of the spell, with half damage on save and no knockback).

The bulette is not simply moving "into another creature's square" which is where the general rule comes from: movement. This result is due to a special ability (spell?) of the bulette.

Specific Beats General

This book contains rules, especially in parts 2 and 3, that govern how the game plays. That said, many racial traits, class features, spells, magic items, monster abilities, and other game elements break the general rules in some way, creating an exception to how the rest of the game works. Remember this: If a specific rule contradicts a general rule, the specific rule wins.

(Basic Rules p. 5)

I'd rule that the specific bulette rule wins over the general rule about "not in the same space" from the movement part of the rules.

Whether a creature is a friend or an enemy, you can't willingly end your move in its space.

(Basic Rules p. 74)

Now what happens?

If the creature has a reaction that allows movement, they can at that point vacate the space during the bulette's turn (character option). Or, they could try to stand up.

At this point, your concern on the "no two things in the same place" is more of a problem during the turns of the creatures that were attacked; it is resolved before the end of each creature's turn.

• Do they back up, stay within reach, and attack?


• Do they back up further and risk an OA?


• Does the character remain prone and in the same space (I'd recommend against) and make attacks (if any) at disadvantage?
  Each character / creature makes their own decision.

At table experience

I recently ran a battle where two bulette's attacked the merchant caravan the players are escorting/guarding, and this exact issue came up. The above is how I ruled.

• One of the poor oxen was dismembered. Of course the party Barbarian, after the battle, quoted a LoTR movie line (Two Towers) and bellowed: "Meat's back on the menu, boys!"

Is this a contradiction?

No, it makes sense from a simulationist / verisimilitude perspective. D&D 5e is not a computer game: it is a TTRPG. There isn't a piece of code that will crash the game if two states "in this space" are both marked as true. The key is that the targets are prone, rather than upright, leaving the bulette astride them at the end of its turn due a special ability: Deadly Leap. Most creatures don't have that ability. The creatures in the prone state have the chance on their turn to deal with it.

One of the principle design tenets of D&D5E is the concept of "exception based design". Otherwise known as "specific over general", the idea is that the general rules apply unless there is a specific rule that says otherwise.

You've correctly recalled the general rule for Moving Around Other Creatures:

Whether a creature is a friend or an enemy, you can't willingly end your move in its space.

The bulette's Deadly Leap ability has no text contradicting the general rule. The references to what happens with a prone target only address what happens during the leap. Without specific text allowing the bulette to remain in place¹, the general rule holds. Because the bulette cannot voluntarily end it's move in another creature's space, it cannot use Deadly Leap if it does not have sufficient movement to clear the target's space after leaping.

Note, however, that the bulette has a Burrow speed. It still needs to make sure it has enough movement left, but it has one option that most characters do not have: down. Your "good reason" is that if the bulette is underground, the surface dwellers can't fight back.

Combine that with it's 60 feet of Tremorsense (meaning it knows where the characters above it are) and a bulette can fight by repeatedly leaping out of the ground, landing on people, then disappearing back underground. The player character answer is Ready actions to whack it when it surfaces next.

¹_{Swarms, for instance say: "The swarm can occupy another creature's space and vice versa, and [...]"}

The monster manual indicates that the bulette possesses the space at the end of the Deadly Leap.

"If no unoccupied space is within range, the creature instead falls
prone in the bulette's space."

While I like the answer about burrowing, it is not necessary. Picture a humanoid being pinned down by the shoulders by a bear / lion/ bulette during an attack. These creatures certainly occupy the same space during the attack.

Therefore, since it is the bulette's space, they do not have to move away from it.

A move and a turn are not the same thing

As seen in most of the other answers,

Whether a creature is a friend or an enemy, you can't willingly end your move in its space.

(Basic Rules p. 74)

The rule specifically says you can't end your move in another creature's space, but that doesn't mean you can't end your turn there. With that in mind, I would rule it perfectly legal for the creature and player to share that space for as long as neither one tries to move... assuming of course that the initial "if no unoccupied space is within five feet" clause is met during the Deadly Leap.

In other words, I'd consider it to technically have ended its move at whatever location from which it launched Deadly Leap. So, if you consider the move to be a subset of the turn, rather than being the turn itself, then it is able to end its turn in the same space as a player character, as long as it didn't use its move to enter that space.

Also, I'd invoke Rule of Cool here and say that a creature pinning a character down for some time while they thrash around with each other is (probably) more dramatic than the creature kindly stepping aside to give them some space.

With regard to swarms and the like, which are explicitly allowed to occupy other creatures' space and vice versa, I would rule that both parties can willingly end movement in the other's space, contrary to the movement rule quoted above.