In
NetHack, an extremely annoying
creature that proliferates throughout the
Dungeons of Doom. They will systematically rob you blind unless you take preventative (or evasive) measures, going first for
rings of adornment, then
weapons and
armor, then everything else.
Nymphs come in several varieties, including mountain nymphs and water nymphs. The latter are sometimes "attracted" (in NetHack's demonic terminology, this means "instantly created next to you") if you drink from a fountain.
Of course, the DevTeam has human (or elven, or dwarven, or gnomish) sexuality nailed -- the Nymph prances around in her birthday suit, and the hapless man immediately begins taking off his boots, cloak, etc so he can get in on the action. Females aren't safe either anymore, in this day and age.
To avoid having your stuff stolen (if your armor class is high enough that they can hit you), drop all of it on the square you are standing upon and attack with spells or other long-range attacks. If you are carrying a ring of adornment, the nymph will attempt to steal this first -- in fact, the only good use for this item is as nymph-bait.
Nymphs are not particularly difficult to kill, but they teleport to a random location on the level each time they successfully steal something, until you are naked, weaponless, and void of items, wandering the level in a pathetic heap. At this point, the nymph will be wearing your cloak of magic resistance +3, your blessed speed boots +4 and ring of regeneration, making her an impossible target. You will then encounter a horde of orcs, a leucrotta, or something else equally nasty and meet your bitter end. Thus, the appearance of a nymph is often cause for definite alarm.