I've got a bunch.
One was where I was drinking out of a fountain and a dark frog popped out and befriended me.
Later on in UT2 or 3, the Dark Frog was fighting something off screen and I ran in to help. The attacker took my leg off, and I was dissolved in Dark Frog blood.
Another one was where I was completely raped by a pack of blink dogs in UT2.
And of course, my favorite, I was attacked by an entire company of Kamikaze Dwarves. In UT3. I wish I was joking.