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If a creature like the Grick Alpha (MM, page 173) has to do an opportunity attack against a PC that is moving out of the Grick Alpha's reach (10 ft), can the DM choose which attack to use?

The Grick Alpha has 3 different attacks and all are described as Melee Weapon Attacks:

Tail. Melee Weapon Attack: +7 to hit, reach 10 ft., one target. Hit: 11 (2d6 + 4) bludgeoning damage.

Tentacles. Melee Weapon Attack: +7 to hit, reach 10 ft., one target. Hit: 22 (4d8 + 4) slashing damage.

Beak. Melee Weapon Attack: +7 to hit, reach 10 ft., one target. Hit: 13 (2d8 + 4) piercing damage.

marked as duplicate by daze413, Ruse, Sdjz, Miniman, Grosscol Oct 11 at 13:44

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  • Since all of the grick alpha's attacks have reach, are you asking whether/how the DM chooses between melee weapon attacks that all have the same reach when making an opportunity attack? Or are you trying to ask a broader question, not specific to the grick alpha? – V2Blast Oct 11 at 7:45
  • The flagged Q is specifically about attack options with different reach. This Q already presumes that multiple options exist. – Szega Oct 11 at 8:59
up vote 1 down vote accepted

Yes, the DM can choose which Melee attack to use.

Since all of the Grick's listed attacks are Melee Weapon Attacks, the DM is free to choose whichever they wish.

It gets a bit trickier when the creature has melee attacks with differing reaches (e.g. a 5ft bite and a 10ft claw). The rules are unclear as to whether or not a creature is only able to make an opportunity attack with its longest reach attack or whether the 5ft bite could be used (provided that the target started its movement within 5ft of the creature). Regardless, the Opportunity Attack would only be triggered if the target moved to a square more than 10ft away from the creature (it wouldn't trigger the Bite while moving from 5ft to 10ft away, for example).

  • 2
    "The rules are unclear as to whether or not a creature is only able to make an opportunity attack with its longest reach attack or whether the 5ft bite could be used (provided that the target started its movement within 5ft of the creature)." - From a player character perspective, this is now 100% clear after the PHB errata: "Reach (p. 147). This property also determines your reach for opportunity attacks with a reach weapon." – V2Blast Oct 11 at 7:38
  • 2
    This is also confirmed by Crawford here: "The SA answer is only about making an opportunity attack with the reach weapon, not with another reach you might have. [...] 'Your reach' means whatever reach of yours is relevant at the moment." His mention of "SA" is referencing the answer about reach and opportunity attacks in the Sage Advice Compendium. – V2Blast Oct 11 at 7:40

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