Hardhat Beetle (5e Creature)
From D&D Wiki
Medium monstrosity, unaligned
Damage Vulnerabilities bludgeoning damage from falling
Charge. If the beetle moves at least 10 feet straight toward a target and then hits it with a slam attack on the same turn, the target takes an extra 4 (1d8) bludgeoning damage. If the target is a creature, it must succeed on a DC 13 Strength saving throw or be pushed up to 10 feet away and knocked prone.
Pushover. The hardhat beetle has disadvantage on ability checks to avoid being shoved.
Slam. Melee Weapon Attack: +3 to hit, reach 5 ft., one target. Hit: 5 (1d8 + 1) bludgeoning damage.
Found primarily in dark caves and dank ruins, hardhat beetles are inherently aggressive towards any strange creatures who enter their territory. Few foes are able to pierce their rebounding shells, which the beetles use both to protect themselves and to slam away would-be predators.