Helm of the Ram

Wondrous item, rare (requires attunement)

While wearing this silver helmet, you can't be moved against your will. Furthermore, once per turn when you make an unarmed strike, you can choose to make the attack with your head. On a hit, the target takes 1d10 force damage, instead of the bludgeoning damage normal for an unarmed strike, and is pushed up to 5 feet away from you. If you moved 20 or more feet straight toward the target immediately before making this attack, you have advantage on the attack roll, and on a hit, the target is pushed up to 10 feet instead.

If a pushed target strikes a solid surface or another creature that is larger than it, the target takes 1d6 bludgeoning damage for every 5 feet it was pushed. If the target is pushed into another creature that is its size or smaller, that creature must succeed on a DC 13 Strength saving throw or take the same damage and be knocked prone.

Ring of the Ram. If you're also attuned to a ring of the ram, you gain a +1 bonus to AC while wearing the helmet, and the helm's Strength save DC is increased to 15.

"You're about to have a baaaaah'd day."