Yeah, life carries a baseball bat and is prone to hitting people with it. Just take the lemons it throws at you and wing them back. This will stun it for 3-5 secs and give you time to get in a strike or two with your sword. Quickly flee afterwards as this does not last, and it may release a wave of dark energy afterwards. Repeat. At 50% health of its health left, provided you have kept yours up and drank a lot of magic potions, it should become relatively easy.