Can an Otyugh use Tentacle Slam twice per turn?

Question

The statblock for the Otyugh in the Monster Manual (p. 248) says:

Multiattack. The otyugh makes three attacks: one with its bite and two with its tentacles.

Bite. Melee Weapon Attack: +6 to hit, reach 5 ft., one target. Hit: 12 (2d8 + 3) piercing damage. If the target is a creature, it must succeed on a DC 15 Constitution saving throw against disease or become poisoned until the disease is cured. Every 24 hours that elapse, the target must repeat the saving throw, reducing its hit point maximum by 5 (1d10) on a failure. The disease is cured on a success. The target dies if the disease reduces its hit point maximum to 0. This reduction to the target's hit point maximum lasts until the disease is cured.

Tentacle. Melee Weapon Attack: +6 to hit, reach 10 ft., one target. Hit: 7 (1d8 + 3) bludgeoning damage plus 4 (1d8) piercing damage. If the target is Medium or smaller, it is grappled (escape DC 13) and restrained until the grapple ends. The otyugh has two tentacles, each of which can grapple one target.

Tentacle Slam. The otyugh slams creatures grappled by it into each other or a solid surface. Each creature must succeed on a DC 14 Constitution saving throw or take 10 (2d6 + 3) bludgeoning damage and be stunned until the end of the otyugh's next turn. On a successful save, the target takes half the bludgeoning damage and isn't stunned.

If the Otyugh starts its turn and is already grappling two PCs, can it use Tentacle Slam twice plus a Bite attack?

Answer 1

No

Tentacle Slam is not technically an attack.

In the stat block, the other actions include the phrase Melee Weapon Attack while Tentacle Slam has no similar verbiage. Tentacle Slam does not call for making an attack roll with a d20.

Tentacle Slam is an action that causes grappled creatures to make saving throws. It does not qualify as an attack for the purposes of the Otyugh's Multiattack ability.

When an attack is not an attack

This prior answer explains what counts as an attack in the game mechanics. That answer draws upon the passage from the Player's Handbook:

If there's ever any question whether something you're doing counts as an attack, the rule is simple: if you're making an attack roll, you're making an attack (PH, p. 194)

There are many actions that would likely be considered "attacks" in-universe, but which are not attacks mechanically. Examples include grappling and spells with save versus damage effects.

When reading a term in the rules, interpret it with the definitions in the rules. When deciding how NPCs/monsters react to something, use common sense.

Answer 2

No, because Multiattack says the Otyugh can use "Tentacle" twice, and that's a different attack from "Tentacle Slam".

If the Otyugh wants to use Tentacle Slam, it needs to use its entire Action to do so.

Answer 3

No

That said, it is probably useful to dig deeper into what it can do based on its attack descriptions.

Based on the verbiage of the Otyugh's ability and the following data from the Sage Advice Compendium, we can look at this deeper, because what an Otyugh can do in this situation is not an easy question (though I understand that it is more than you asked for).

Is the grappling rule in the Player’s Handbook usable by a handless creature?

The grappling rule (PH, 195) was written for a grappler with at least one hand, but a DM can easily adapt the rule for a handless creature that has a bite or an appendage, such as a tentacle, that could reasonably seize someone. A wolf, for example, could plausibly try to seize a person with its bite, and the animal wouldn’t be able to use its bite attack as long as it held onto the person. Keep in mind that the grappling rule in the Player’s Handbook requires the Attack action, so a creature must take that action—rather than Multiattack or another action in the creature’s stat block—when it uses that rule. A monster, such as a roper, that has a special grappling attack doesn’t follow that rule when using its special attack.

Additionally, the description of the Otyugh's attacks state that each tentacle can hold up to one creature, for a max of two.

Let's analyze the actual attack structure of the Otyugh

The Otyugh has four basic forms of attacks in most scenarios: A tentacle slam, a bite, a tentacle attack, and multi-attack. Of these only two are actually considered attacks for the purposes of an Otyugh attacking a grappled target: Bite and tentacle. Both of these state that they are attacks in their description.

While the Otyugh has a special grappling attack as per its stat-block (tentacle), only that attack is listed as having special rules. The bite or the tentacle attack can be used, but multi-attack is a separate action from the "attack action."

Generally speaking, it would be best for the Otyugh to grapple two targets simultaneously, if possible, and use Tentacle Slam in subsequent rounds.

Additionally, Tentacle Slam is not the same as a Tentacle attack.

Answer 4

NO, because you are substituting Tentacle Slam for Tentacle. The Otyugh has four options for it's action in terms of attacking:
1 x Multiattack
1 x Bite
1 x Tentacle
1 x Tentacle Slam
If you choose Multiattack then you can make 3 attacks: 1 Bite and 2 Tentacles.

Answer 5

No

Multiattack is an action that specifically states which attacks may be used. Tentacle Slam in this case is a separate action it may take on its turn instead of the Multiattack

While the other answers state that Tentacle Slam is not an attack (as it lacks the Melee Weapon Attack qualifier), that does not immediately disqualify it from the Multiattack feature (see the Black Dragon stat block below). It should also be noted that even if it had a third attack (or the slam was an attack), it could still not use it with multiattack unless stated as such.

Creatures with a multiattack ability that allow it to sub out an attack for another will indicate that the substitution may be made in the stat block.

For example, here is the multiattack feature for the Wight:

Multiattack. The wight makes two longsword attacks or two longbow attacks. It can use its Life Drain in place of one longsword attack.

In this case, the Wight may substitute a Life Drain in place of a long sword attack.

As for additional attacks not included in multiattack, here is the Adult Black Dragon stat block.

Multiattack. The dragon can use its Frightful Presence. It then makes three attacks: one with its bite and two with its claws.

Bite. Melee Weapon Attack: +11 to hit, reach 10 ft., one target. Hit: 17 (2d10 + 6) piercing damage plus 4 (1d8) acid damage.

Claw. Melee Weapon Attack: +11 to hit, reach 5 ft., one target. Hit: 13 (2d6 + 6) slashing damage.

Tail. Melee Weapon Attack: +11 to hit, reach 15 ft., one target. Hit: 15 (2d8 + 6) bludgeoning damage.

Frightful Presence. Each creature of the dragon's choice that is within 120 feet of the dragon and aware of it must succeed on a DC 16 Wisdom saving throw or become frightened for 1 minute. A creature can repeat the saving throw at the end of each of its turns, ending the effect on itself on a success. If a creature's saving throw is successful or the effect ends for it, the creature is immune to the dragon's Frightful Presence for the next 24 hours.

Acid Breath (Recharge 5–6). The dragon exhales acid in a 60-foot line that is 5 feet wide. Each creature in that line must make a DC 18 Dexterity saving throw, taking 54 (12d8) acid damage on a failed save, or half as much damage on a successful one.

In this case, we can see that the Multiattack action does not include its Tail attack, despite qualifying as a Melee Weapon Attack, and instead may use Frightful Presence, which is not a melee attack.