Leprechauns are originated from Irish mythology. An oft view of Leprechauns is that they are unorthodox creatures, unusually short in height, some reports describe them to be no taller than 3 feet. Leprechauns in traditional lores, wear a green hat fronting a golden four-leaf clover with a suit and a buckle on its belt. Leprechauns are said to be keepers of gold and treasure, in some narrations, people who sought to steal a Leprechauns gold, turn Leprechaun into sad beings since the gold collected by Leprechauns are the pivotal objective of their living. 
Another view of the Leprechauns speaks that sighting them might bring good luck. Rainbows are also associated with Leprechauns, since treasure is said to be located at the end of the rainbow, the guardian of the treasure is assumed to be a Leprechaun.
Grand Theft Auto IV included an Irish shop in Alderney called Leprechaun's Winklepicker. Ever since there have been vague reports of its existence in the game, however, the sightings are never documented and the few investigations that took place remain unsolved. Leprechauns are the basis of myths such as the likes of Dwarves and Bridge Trolls in Grand Theft Auto: Vice City and these myths are a predecessor to the myth in GTA IV, only with different names due to varying description and sightings.