Homebrew
Multiattack. The Helmasaur King makes two Claw attacks and one Tail Swipe.
Claw. Melee Weapon Attack: +12 to hit, reach 5 ft., one target. Hit: 13 2d6+6 bludgeoning damage.
Tail Swipe. Melee Weapon Attack: +15 to hit, reach 10 ft., one target. Hit: 21 3d8+6 bludgeoning damage plus 12 1d10+6 piercing damage.
Headbutt (Recharge 4-6). The Helmasaur King headbutts a target, pushing them back 10ft and knocking them prone.
Melee Weapon Attack: +15 to hit, reach 5 ft., one target. Hit: 28 4d10+6 bludgeoning damage.
Roll. The Helmasaur King rolls forward, knocking away creatures in the process.
Moves up to 20ft. Any creatures cought in the path must make a DC 13 Dexterity save to avoid getting hit.
Deals 13 2d6+6 damage on a failed save, and knocks creatures to the side. No damage on a successful save.
Dessert
Arid wilderness