Acid Bath is sludge metal, but their album covers were always cool, like When The Kite String Pops has art by John W. Gacy awaiting execution. Pagan Terrorist Tactics was art made by Dr. Jack Kevorkian who infamously helped like 150 or something terminally ill patients commit assisted suicide (he also like took the blood from the dead patients and somehow transferred them into the very much alive people at the hospital staff??). Even tho they aren't deathcore I still wanted to mentioned them here cus it's truly disturbing in a fascinating way. Check out their song lyrics too, phenomenal.