Half decayed Wyvern, its ribs are exposed, as is half of it's skull, the flesh that does remain is dark black and leathery, It's eyes are glowing dark blue/black. There is a blue/black glow that emanates from all of the exposed areas where the skin and flesh have rotten away.

Multiattack. The wyvern makes two attacks: one with its bite and one with its stinger. While flying, it can use its claws in place of one other attack.

Bite. Melee Weapon Attack: +6 to hit, reach 5ft, one target 2d6+2 piercing +2 necrotic damage

Claws. Melee Weapon Attack: +6; to hit, reach 5 ft., one target, 2d6+2 slashing damage +2 necrotic damage.

Stinger. Melee Weapon Attack: +6 to hit, reach 10 ft., one creature. 2d6 piercing damage. The target must make a DC 15 Constitution saving throw, taking 2d6 necrotic and 2d6 poison damage on a failed save, or half as much damage on a successful one.