Mammoth

Trampling Charge. If the mammoth moves at least 20 feet straight toward a creature and then hits it with a Gore attack on the same turn, that target must succeed on a DC 17 STR save or be knocked prone. If the target is prone, the mammoth can make one Stomp attack against it as a bonus action.

Multiattack. The mammoth makes two Gore attacks.

Gore. _Melee Weapon Attack:_ +9 to hit, reach 10 ft., one target. _Hit:_ 22 (3d10+6) piercing damage.

Stomp. _Melee Weapon Attack:_ +9 to hit, reach 5 ft., one prone creature. _Hit:_ 19 (3d8+6) bludgeoning damage.

Trunk Grab. The mammoth grabs one Large or smaller creature within 10 feet of it. The target must succeed on a DC 17 STR save or be grappled (escape DC 17). Until this grapple ends, the target is restrained, and the mammoth can't use Trunk Grab on another creature.