The Formageddon is a bit easy to deal with.

Compared to Eema who had help of several annoying Minions and large scale area damage, The Formageddon's attacks were easier to avoid, as long as we can guess his attack direction.

He's also easy to approach and we can sometimes hit him with melee attacks. So i combined ranged attack as my main weapon, and adding a spell which damaging the enemy close to me.