Nidhogg (5e Creature)
From D&D Wiki
Large dragon, any evil alignment
Multiattack. The nidhogg makes three attacks: one with its bite and two with its claws.
Bite. Melee Weapon Attack: +7 to hit, reach 10 ft., one target. Hit: 11 (2d6 + 4) piercing damage, plus 5 (2d4) poison damage.
Claw. Melee Weapon Attack: +7 to hit, reach 5 ft., one target. Hit: 9 (1d10 + 4) slashing damage.
According to legend, the nidhogg were once gigantic feathered dragons that roamed the planes freely, gorging themselves on whatever they could find, until they were banished by the gods to the Lower Planes. Now, they are scaly and serpentine, and they hatch foul plots and make alliances with unspeakable evils, awaiting the day that they can strike against the gods that imprisoned them there.