The hezrou, &, is a demon in NetHack. They are slow, but can hit hard. If you polymorph into one and you hit a monster with bare or gloved hands you have 1/13 chance per hit (like any demon other than balrog and foocubus) landed to summon tame demons with "Some hell-p has arrived!" message.
Polymorphing into a hezrou (by polytrap) is not a very good idea: they are very slow and large. You will break your shirt, cloak and any body armor. A good idea (for low level charsters) is to use only bare handed attacks to summon some tame hezrou.
Encyclopedia entry Edit
"Hezrou" is the common name for the type II demon. It is
among the weaker of demons, but still quite formidable.