The Leech is a worm type enemy spawned by the Wall of Flesh. Multiple leeches are dropped from its mouth in groups of 3-4. The groups will get larger as the boss gets damaged.These should be killed as soon as possible, as large groups can kill the player quickly. Eventually, the Wall of Flesh will release them in a continuous stream.
The Leech has 3 parts:Head, Body and Tail.
-There is a rumor that the leech restores health to the WoF when it damages the player.