A leprechaun is a type of fairy in Irish folklore, usually taking the form of an old man, clad in a red or green coat, who enjoys partaking in mischief. Like other fairy creatures, leprechauns have been linked to the Tuatha Dé Danann of Irish mythology. Popular depiction shows them as being no taller than a small child.
"A fairy of Irish descent, pictured as an old man wearing a red hat. He repairs the shoes of other fairies when they wear out their soles while dancing. He also knows the location of treasures. Legend has it that a man caught a leprechaun, only for it to disappear before he realized what he had."