Slam

Melee Weapon Attack: +4 to hit, 5 ft., one target, 7 (2d4+2) bludgeoning damage.

Harvester's Stampede (Recharge 5-6)

Moves up to its speed in a straight line and can move through the space of any Large or smaller creature. The first time the harvest horse enters a creature's space during this move that creature must make a DC 12 Dex save. On a failure it takes 7 (2d6) slashing damage and is knocked prone. On a success it takes half damage and isn't knocked prone. When the harvest horse moves in this way it doesn't provoke opportunity attacks.