Recently, I was playing Nethack (doing reasonably well) and has a little dog as a pet. However it suddenly attacked me while I had low health, killing me instantly. It had been tamed for several levels, and I'd fed it well, giving it all corpses and sometimes more.
What is the reason for this strange behaviour?
Best Answer
There are too many possibilites to know for sure without more information:
Your pet could have been confused. There are several ways this could have happened: another monster (ex. umber hulks have a confusion gaze), a thrown potion of confusion or booze, etc.
Your pet could have been blind. There are several possibilities for this as well: a thrown potion of blindness, the explosion of a yellow or black light, the zap of a wand of lightning, etc.
Your pet could have been affected by conflict. Did you happen to try on an unidentified ring shortly before this occurred? (There are other ways of obtaining conflict, but it's unlikely that you had access to it if you were at a low enough level to be killed by a little dog.)
It could have just been a different little dog. Do you have a ttyrec (many public servers automatically record them for you)? If so, you could go back and check to see whether it was really your own dog that killed you. Seems like an unlikely mistake, but I've made it before...