A leprechaun is a NetHack monster whose main attack is to steal some of your gold (or gold you are standing on) and teleport away. This makes them, primarily, annoyances. Eating a leprechaun's corpse has a 50% chance of conveying teleportitis. You will also gain teleportitis if polymorphed into a leprechaun. Leprechauns are normally generated sleeping and with LDd30 pieces of gold.
When you attack a leprechaun which is not frozen, asleep, confused, or blind, it has a 1/7 chance of moving one square away instead of being hit. If they successfully evade, you will move instead of attacking.
Leprechaun halls exist in the NetHack dungeon; these are special rooms filled with many, many leprechauns as well as gold.
Leprechauns are the only member of the monster class of the same name.
Leprechauns are best attacked with ranged weapons or spells. You can also prevent them from teleporting by hiding all your gold in a container or on a distant floor space. However, don't stand right on top of gold while fighting them, as they will grab it from under your feet and teleport away. Alternatively, throw your gold at them, then run the fleeing leprechaun into a corner. With no gold on your person, the leprechaun will be unable to make a theft-teleport.
Leprechauns can be exploited for credit cloning: drop all but one of your gold coins in a shop, lure a leprechaun inside, let it pick up the pile of gold, then let it hit you or just teleport out. Then find it and kill it to get your gold back, and you'll still have your credit. Since you can only do this once per leprechaun, you should do it with as much gold as possible. Using leprechauns this way is difficult since, unlike pets, they won't follow you; but it does mean you can credit clone even without a pet and (in 3.6.0) without a sack.
If you are a knight, awaken leprechauns before attacking them to avoid alignment penalties. Using the ring of conflict in a leprechaun hall will cause them to steal from each other- this will annoyingly scatter them across the level.
For most players the leprechaun poses no real threat- however its predilection to escape rather than fight can make it time-consuming to kill. A problem occurs when a leprechaun equips himself with an escape wand such as teleportation or make invisible. Worst of all is a wand of digging. Such a leprechaun may be in a position to avoid your retribution, plunging straight through the floor as soon as you corner it.
Polymorphing into a leprechaun lets you steal gold from monsters. Generally, this is rather pointless, because shopkeepers support credit cloning, priests are too powerful when you still need protection, and other monsters can simply be killed.
The Irish Leprechaun is the Faeries' shoemaker and is known
under various names in different parts of Ireland:
Cluricaune in Cork, Lurican in Kerry, Lurikeen in Kildare
and Lurigadaun in Tipperary. Although he works for the
Faeries, the Leprechaun is not of the same species. He is
small, has dark skin and wears strange clothes. His nature
has something of the manic-depressive about it: first he
is quite happy, whistling merrily as he nails a sole on to a
shoe; a few minutes later, he is sullen and morose, drunk
on his home-made heather ale. The Leprechaun's two great
loves are tobacco and whiskey, and he is a first-rate con-man,
impossible to out-fox. No one, no matter how clever, has ever
managed to cheat him out of his hidden pot of gold or his
magic shilling. At the last minute he always thinks of some
way to divert his captor's attention and vanishes in the
twinkling of an eye.
by Nancy Arrowsmith & George Moorse ]