Blood Skeleton

Thick Blood. These skeleton's are bloody because of bone marrow inside of them. Blood seeps from the bone, giving it the seems that the Skeleton is constantly bleeding. This blood however, is cursed by Vampiric magic to actually reinforce the skeleton, making it more durable. The skeleton gains resistance to piercing and slashing damage.

Ravenous Hunger. Due to the constant bleeding, these Skeleton become more animalistic. They need to maintain their blood levels or they will die. When the Blood Skeleton finds a corpse, it will attempt extract its blood with its fangs as a bonus action. As the creature consumes blood on that turn, they satisfy their hunger and gain 2d4 temporary hit points, sending them into a frenzy.

Frenzy. The creature becomes frenzied at anytime it has temporary hit points. While this frenzy is active, the Skeleton can make one extra bite attack, one extra claw attack and its movement speed is increased by 20 feet.

The Blood Skeleton makes one bite attack and one claw attack.

Bite. Melee Weapon Attack: +4 to hit, reach 5 ft., one target. Hit: 1d4 + 2 piercing damage and 1d12 + 2 Necrotic damage. The Necrotic damage saps Blood from the creature and gives the Skeleton temporary hit points equal the Necrotic damage.

Claw. Melee Weapon Attack: +4 to hit, reach 5ft., one target. Hit: 1d12 + 2 slashing damage and 1d4 + 2 Necrotic damage.  The Necrotic damage saps Blood from the creature and gives the Skeleton temporary hit points equal the Necrotic damage.