Otherworldly Obsidian Charger

Traits

Life Bond. When you regain Hit Points from a level 1+ spell, the charger regains the same number of Hit Points if you're within 5 feet of it.

Dominator. While riding the charger, the rider deals extra damage equal to the spell's level when they hit a creature that has the Prone condition with a melee attack.

Shared Ward. Requires a level 5+ spell. While riding the charger, its rider also has Resistance to Bludgeoning, Piercing, and Slashing damage from nonmagical attacks.

Greater Ward. Requires a level 7+ spell. The charger has Immunity to Bludgeoning, Piercing, and Slashing damage from nonmagical attacks rather than Resistance, and its rider shares that Immunity while riding the charger.

Actions

Hooves. Melee Attack Roll: Bonus equals its Strength modifier plus your Proficiency Bonus, reach 5 ft. Hit: 2d6 + its Strength modifier Bludgeoning damage.

Trample (1/Day). Requires a level 4+ spell. The charger must have moved at least 30 feet in a straight line this turn. It keeps moving in that line, and it can enter the spaces of Large or smaller creatures during this move. Strength Saving Throw: DC 10 + the spell's level, each creature whose space the charger enters for the first time. Failure: A number of d10s equal to the spell's level Bludgeoning damage, and the target has the Prone condition. Success: Half damage, and the target keeps its footing. The charger can't end this move in another creature's space.