Shelgon (5e Creature)
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Small dragon, any alignment
Rock Head. The shelgon takes half the damage from critical hits. This does not prevent any additional effects due to critical hits, such as that of a vorpal sword.
Plummet. The shelgon has resistance to falling damage.
Reckless. At the start of its turn, the shelgon can gain advantage on all melee weapon attack rolls it makes during that turn, but attack rolls against it have advantage until the start of its next turn.
Overcoat. The shelgon can breathe normally in any environment, and it has advantage on saving throws made against harmful gases and vapors (such as cloudkill and stinking cloud effects, inhaled poisons, and the breath weapons of some dragons).
Headbutt. Melee Weapon Attack: +6 to hit, reach 5 ft., one creature. Hit: 12 (2d8 + 3) bludgeoning damage, and the shelgon takes the same amount as recoil damage.