Mage casting falling frost on himself and suiciding....

[Wauthan]

Well if all my friends were maneating abominations I would have been pretty depressed as well.

Jokes aside you propably went up against some kind of flying units, like say the products of a Swarm spell, and your unguarded mage panicked and cast the highest area damage spell he knew. The friendly fire issue aside I've yet to see a caster unit deliberatly kill itself.