Multiattack

The thrummren makes two attacks: one with its gore and one with its hooves.

Gore

Melee Weapon Attack: +9 to hit, reach 15 ft., one target. Hit: 24 (3d12 + 5) piercing damage plus 10 (3d6) lightning damage.

Hooves

Melee Weapon Attack: +9 to hit, reach 10 ft., one target. Hit: 14 (2d8 + 5) bludgeoning damage plus 10 (3d6) thunder damage.

Thunder Stomp (Recharge 5-6)

The thrummren rears back and slams its front hooves into the ground. Each creature within 20 feet of the thrummren must make a DC 17 Strength saving throw. On a failure, a creature takes 35 (10d6) thunder damage, is pushed up to 10 feet away from the thrummren, and is deafened until the end of its next turn. On a success, a creature takes half the damage and isn't pushed or deafened.