Gameplay Element Concept: Enrage

The basic idea is that it's like taunt, except that the taunted enemy expends their spells to deal damage as well. The idea is that the enraged champion has lost their wits and actually wants to kill the 'enrager.' From a gameplay/balance perspective, this would be a mechanic that could be given to more powerful bruisers or assassins so that they risk their life when they use it. Enraged enemies shouldn't use their ultimates as that would probably be very annoying for the enraged player.

My question is, not whether or not this idea would fit in league (though you may address that), but rather if it would be good, who it would be good on, and who it would be broken on.

~crimsoncobra3