Putrefier

Putrefier [actual game spelling] is a neon-green Balron that spawns in the westernmost part of the Palace of Paroxysmus. He drops "Spleen of the Putrefier", one of the 4 keys needed to fight Chief Paroxysmus. This things is no joke -- it will rip you to pieces if you aren't careful. Its powerful melee attacks hit for about 50 damage (more unless you have 70 resists), and with plenty of magic to top that off it is probably one of the toughest of the new ML named creatures. The safest method of fighting it is to Energy Field the small entrance to where it spawns, so that it is trapped in the area, and cast energy based spells and Energy Vortexes over the wall. Archers work great firing over the wall too. It can drop a paragon chest, deviously drawn treasure maps, and pretty good loot.