Wyvern is a Large dragon with unaligned alignment and Challenge Rating 6 in the 2024 SRD. This stat block includes AC 14, 127 hit points, speeds, traits, and actions.
Multiattack - The wyvern makes one Bite attack and one Sting attack.
Bite - Melee Attack Roll: +7, reach 5 ft. Hit: 13 (2d8 + 4) Piercing damage.
Sting - Melee Attack Roll: +7, reach 10 ft. Hit: 11 (2d6 + 4) Piercing damage plus 24 (7d6) Poison damage, and the target has the Poisoned condition until the start of the wyvern’s next turn.