Moon Leech Clot

The Moon Leech Clot is a special type of enemy which is taken from the player when the Moon Lord's tongue grabs hold of the player. They don't pose as much of a threat to the player, as they deal no damage. However, if one manages to reach the Moon Lord's mouth before it is killed, a part of the boss will be healed by 1000 HP. Since they have no defense, though, they can be destroyed fairly easily with most Hardmode weapons.

Trivia

 * They look exactly like the Living Ultrabright Fire Block sprite-wise, but they are not animated.