Top-level spell "Arcane Swarm" has random targets and several missiles. I think it's malfunctioning, far as I can tell, because all missiles target the same "enemy" and that means every rock-fall, barrel, totem, etc. is counted as an "enemy" -- in a room with 1 enemy, I cast it, and all 4-5 missiles target fallen rocks. Or 1 of the 5 enemies surrounding me.
I would expect that each missile targets separately, and I would think it means creature enemies -- although totems would be fine, barrels and rocks shouldn't be a target. I don't want to be spending that type of skill points and mana if it's basically useless to cast it...even if all missiles targeted a totem, it's frustrating.
[Been testing lots of combos and using strange skills just to try to help with the zombasite skill/balance question...]