The gaze attack has a fairly low accuracy: there is a 75% chance that it will miss plus another 66% if you are either invisible or displaced. If you are reflecting and the gaze would have connected, then it will kill the gazer.
Although the catoblepas is not randomly generated, it is a valid polymorphable form, so it is perfectly possible for a chameleon or intelligent monster with a wand of polymorph or polymorph trap to suddenly turn into a catoblepas. It is also possible to self polymorph into a catoblepas, but beware of monsters with reflection, as a reflected gaze of death will kill you even if you have reflection yourself.
Strangely, the catoblepas is a unique monster, yet also genocidable. This is mostly irrelevant, but if you wish for the corpse of one in wizard mode, it will be described as "The catoblepas' corpse" rather than "A catoblepas corpse."
The Catoblepas is, as in Ethiopia, a mid-sized herbivore with a body of a buffalo and a head of a boar. Its gaze and breath was thought to turn man to stone, or kill them in some way. Due to the weight of its head, it is usually looking downwards.