Homunculus

From Wikihack

The homunculus, i, is a minor demon in NetHack. Its bite can put unwary adventurers to sleep. While the bite attack is not as deadly as the floating eye's gaze, it can still present a significant hazard. Its corpse is poisonous and has a small chance of conveying poison or sleep resistance. They will normally be peaceful if you are appropriately chaotic.

Since they can potentially put you to sleep, it is best to take them out with ranged attacks or avoid them altogether. Sleep resistance will nullify their sleeping bite, making it safer to fight them hand-to-hand, as they do an utterly unthreatening amount of damage.

Their corpse is poisonous and will reduce your strength if you do not have poison resistance.

[edit] Encyclopedia entry

A homunculus is a creature summoned by a mage to perform some
particular task.  They are particularly good at spying.  They
are smallish creatures, but very agile.  They can put their
victims to sleep with a venomous bite, but due to their size,
the effect does not last long on humans.

"Tothapis cut him off.  'Be still and hearken.  You will travel
aboard the sacred wingboat.  Of it you may not have heard; but
it will bear you thither in a night and a day and a night.
With you will go a homunculus that can relay your words to me,
and mine to you, across the leagues between at the speed of
thought.'"
        [ Conan the Rebel, by Poul Anderson ]