He is the entity that brings presents to good boys and girls on Halloween night, as popularized on the Peanuts television special "It's The Great Pumpkin, Charlie Brown".
It is believed the legend of the Great Pumpkin originated in 12th century Ireland at a time when the Irish were still carving turnips into Jack-O-Lanterns for their Hallow's Eve festivities. According to legend the young children who carved the turnips were frustrated over the difficulty in carving this small root vegetable. Their wee fingers kept getting nicked by their knife blades when the knives slipped on the smooth surfaces of the turnips. The story goes that one such child, a 7 year old by the name of Phaneus, prayed on the evening of October 30 before he went to sleep, for divine intervention to bring him an easier vegetable to carve.
When he awoke the next morning beside his bed was a strange orange globelike vegetable twice the size of his head. When Pheneus touched it he realized this was the answer to his prayer, and he therefore immediately and gleefully began carving it into a Jack O' Lantern.
Upon carving what we know today as the pumpkin, he showed his creation to the other children of his village, and initially they were so afraid. But then the glory of the higher power shone about them, and said, "Behold, I give you tidings of great joy, for this is the Great Pumpkin; peace on Earth, good will towards men.
"The Great Pumpkin rises from the pumpkin patch every Halloween to give presents to good boys and girls!"