Tentacles - Giant Octopus

Monster Manual - 5e, D&D Basic Rules

Tentacles. Melee Weapon Attack: +5 to hit, reach 15 ft., one target. Hit: 10 ( 2d6 + 3 ) bludgeoning damage. If the target is a creature, it is grappled (escape DC 16). Until this grapple ends, the target is restrained, and the octopus can’t use its tentacles on another target.