I once killed an Orc while I experienced a kind of animation like known from the fanatic lizards (those wioth these ... orbs).

I guess thia was one "Experience Bomb", but I still can't say for sure.

However, the circumstances direct to it.

When you find a big kettle of crazy, it's best not to stir it.
--Dilbert cartoon

"Interplay.some zombiefied unlife thing going on there" - skavenhorde at RPGWatch