Huge Undead
Armor Class 13
Hit Points 126 (11d12+55)
Speed walk +50
Challenge 8
Damage Vulnerabilities bludgeoning
Damage Immunities poison
Condition Immunities fatigue, poisoned
Senses darkvision 60 ft., passive Perception 9
Undead Nature. A skeleton doesnt require air, sustenance, or sleep.
Multiattack. The skeleton makes a bite attack and a tail attack against two different targets.
Bite. Melee Weapon Attack: +9 to hit, reach 10 ft., one target. Hit: 25 (3d12 + 6) piercing damage. If the target is a creature it is grappled (escape DC 17). Until this grapple ends the skeleton can't bite a different creature and it has advantage on bite attacks against the grappled creature.
Tail. Melee Weapon Attack: +9 to hit, reach 10 ft., one target. Hit: 19 (3d8 + 6) bludgeoning damage.
Source: Level Up Advanced 5e Monstrous Menagerie · OGL/Open