The nalfeshnee, &, is a demon in NetHack. They are one of the few ordinary demons capable of spell-casting and can be considered dangerous in this respect, as a sufficiently high-level one can summon nasties.
Nalfeshnee cannot normally be tamed; however, with figurines they could be created tame, or an existing pet may polymorph into one.
Nalfeshnee pets are strong, with up to 16 hit dice and a max of 128 hit points, but not as dangerous as they are as enemies.
They do not eat, so tameness cannot be increased with food.
They will open unlocked doors, but are stopped by locked doors and boulders, and, as they do not fly, all traps will affect them.
Not only do these demons do physical damage with their claws
and bite, but they are capable of using magic as well.