Bite - Tyrannosaurus Rex

Monster Manual - 5e, D&D Basic Rules

Bite. Melee Weapon Attack: +10 to hit, reach 10 ft., one target. Hit: 33 ( 4d12 + 7 ) piercing damage. If the target is a Medium or smaller creature, it is grappled (escape DC 17). Until this grapple ends, the target is restrained, and the tyrannosaurus can’t bite another target.