Talk:Wall of Flesh/@comment-7745369-20130403021601/@comment-92.17.225.174-20130406165725

It will always spawn if there's one player in the Underworld and if a Voodoo Doll drops in lava, so a deman must have somehow been killed and dropped a doll into the lava. The reason it still spawned despite you not being in the Underwolrd is probably a console glitch.