This troper remembers hearing about a session of ''Mage: The Awakening'' his college friends played that involved transforming a cat into a much larger, stronger and angrier animal. This animal then went on a rampage in a near-by town. Eventually the military was called in to deal with the animal, and fired every gun they had at it (including a few tank rounds).....right when the transforming spell WORE OFF. The math went like this: lots of bullet damage intended for larger animal + cat = "Red Mist". This term has been used by most future games of all systems in that college since.