Okay so I'm at the final boss, the bizarro thing, and all the guides make it sound easy but the fricking thing can heal itself faster than I can kill it and I'm a level 75. Every time I take some significant damage off of it it heals itself by like 7,000 hp OVER AND OVER AND OVER AND OVER, it made me want to kill myself. Is there some trick to killing this thing or is this just an insanely difficult battle?