Ruidium Elephant

If the elephant 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 16 Strength saving throw or be knocked prone. If the target is prone, the elephant can make one Stomp attack against it as a bonus action.

Melee Weapon Attack: +10 to hit (with advantage if the target is a creature missing any hit points), reach 10 ft., one target. Hit: 25 (4d8 + 7) piercing damage plus 7 (2d6) psychic damage.

Melee Weapon Attack: +10 to hit, reach 5 ft., one prone creature. Hit: 29 (4d10 + 7) bludgeoning damage plus 7 (2d6) psychic damage.