This post brought to you by the insanity of 3.5 D&D. Which I love to bits, in many ways for crazy shit like this. Take one energy substitution feat, add a fireball, stir and a short time later: Tada! The Coldball. Or Iceball. Or better yet, the Acidball. Acidball isn't quite as brain twitchy as a fireball doing cold damage. It simply makes your brain short out. Much like you were hit by a fireball that does cold damage. The nonsensical contradictory nature of the result of the rules makes me happy. More so when I get to explain it to someone to see the look on their face.