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: +8 to hit, reach 10 ft., one creature. Hit: 12 (2d6 + 5) piercing damage plus 10 (3d6) poison damage.

Claws

Melee Weapon Attack: +8 to hit, reach 5 ft., one target. Hit: 18 (3d8 + 5) slashing damage and the creature is grappled (escape DC 16). Until this grapple ends, the creature is restrained, and the wyvern can't use its claw on another target.

Stinger

Melee Weapon Attack: +8 to hit, reach 10 ft., one creature. Hit: 12 (2d6 + 5) piercing damage. The target must make a DC 16 Constitution saving throw, taking 24 (7d6) poison damage on a failed save, or half as much damage on a successful one.

Spit Venom (Recharge 5-6)

The wyvern spits venom at a target within 60 feet. The target must make a DC 16 Constitution saving throw, taking 42 (12d6) poison damage on a failed save, or half as much damage on a successful one.