Monsters

What actions can monsters use to make Opportunity Attack? Are Multiattack and breath weapon actions allowed?. When making an Opportunity Attack, a monster can make any single melee attack listed in its stat block. A monster also has the option to make an Unarmed Strike as an Opportunity Attack, following the normal rules of an Unarmed Strike.

An action, such as a breath weapon effect, that doesn't include a melee attack roll isn't eligible to be chosen for an Opportunity Attack. Additionally, a monster can't use its Multiattack when making an Opportunity Attack, because the use of Multiattack specifically predicates on taking the Attack action, and an Opportunity Attack takes a Reaction.

The Monster Manual says gnolls speak Gnoll, but the Player's Handbook doesn't mention that language. What is correct?. The Player's Handbook language tables don't list every language in the D&D multiverse. The Monster Manual mentions other languages, including Modron, Sahuagin, and Slaad.

If a monster makes a melee attack that uses its Dexterity modifier, is it considered to have used a Finesse weapon?. A weapon doesn't have the Finesse property unless its description says so, and using Dexterity for an attack doesn't confer the Finesse property. If a weapon does have that property, you can use Strength or Dexterity with it.

Does a creature with Magic Resistance have Advantage on saving throws against Channel Divinity abilities, such as Turn the Faithless?. Channel Divinity creates magical effects (as stated in both the Cleric and the Paladin). Magic Resistance applies.

If a Shadow rolls a Critical Hit, does it reduce the target's Strength by 2d4, as well as dealing the extra Necrotic damage?. No. A Critical Hit lets you roll damage dice twice. An effect that deals damage is one that reduces the target's Hit Points. The Shadow's Strength reduction isn't damage because it has no effect on the target's Hit Points.

Is a Vampire affected by Hold Person or Calm Emotions?. Many spells affect not just any creatures, but only certain types, as specified in the spell. Hold Person and Calm Emotions work only on Humanoids, and a Vampire is not a Humanoid.

Can a creature that burrows grapple a target and drag them into the ground by burrowing?. No. A burrowing creature can drag another creature with them only if they have the ability to leave a tunnel. For example, a Purple Worm has the Tunneler trait, so it can drag a Grappled creature into a tunnel it creates when burrowing. Conversely, an Earth Elemental can't drag a creature into the ground with it.

Can a Hydra use Reactive Heads to make multiple Opportunity Attacks against one creature at the same time when it provokes?. Yes. For that reason, we recommend taking the Disengage action when you're going to move away from a Hydra.