Funny I never researched this back in the day. I mostly played assassin, and apparently there's a reflect monster trait which meant I was effectively killing myself because my damage far out ranked my health/armor, and thought it was the explosion that occurs when they die. Just remember this mostly being the only thing that ever really killed me consistently on the last section of Hell on Nightmare difficulty. Last time I played D2 was probably 2004.
Sidenote, I'd like to go back and see what a hacked character looks like on today's computer hardware. Once built some assassin claws that would cast every spell in the game on hit. Shit was funny, but made the game run like a slideshow on an Athlon 1700XP running at 2.4ghz. Still. Fun.