Multiattack. The yutyrannus makes two attacks: one with its bite and one with its tail. It can't make both attacks against the same target.

Bite. +10 to hit, reach 10 ft., one target. Hit: 28 (3d12 + 10) 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 yutyrannus can't bite another target.

Tail. Melee Weapon Attack: +10 to hit, reach 10 ft., one target. Hit: 20 (3d8 + 7) bludgeoning damage.

Fear Roar (5-6). The yutyrannus unleashes a terrifying roar. All hostile creatures must succeed a DC 17 Wisdom saving throw or become frightened for 1 minute.