I have a damsel, about 8 years now, that attacks everyone in her territory. Chased a chromis right out of the tank once. Thank God I was standing in front of the tank when it happened. That same chromis has been missing for two days now.
Three theories:
1. It just died and the stars and worms ate the corpse
2. It jumped out of the tank(haven't found the body around, but they can flop around for a good distance)
3. My 3 week old carpet ate him