Bucephalus

Trampling Charge. If the horse moves at least 30 feet straight toward a creature and then hits it with a hooves 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 horse can make another attack with its hooves against it as a bonus action.

Dominating Presence: all creatures within 100ft must pass a wisdom saving throw of 18 or be unable to act until they pass

Hooves. Melee Weapon Attack: +6 to hit, reach 5 ft., one target. Hit: 11 (2d8 + 6) bludgeoning damage.

Bite. Melee Weapon Attack: +6 to hit, reach 5 ft., one target Hit: 11 (2d6+4)

Mighty Stomp: Used as an action all creatures within 30ft must make a dex saving throw of 15 or be made prone

Faster than the wind: As an action this creature is able to dash up to 100ft and make up to 3 attacks

Invulnerable: unable to take damage unless the attacker passes an animal handling check of 18 or above

Indominable: unable to be ridden by any but its true owner unless they pass an animal handling check of 30 or above

the true owner must pass a check of 10