The tradition of carving Jack-O'-Lanterns comes from an Irish myth about a man named "Stingy Jack"

According to the legend, after tricking the Devil into not taking his soul, Stingy Jack was condemned to roam in darkness for eternity. For light, he hollowed out a turnip, placed a burning coal inside, to make a lantern. When Irish immigrants brought the tradition to America, they found that pumpkins, which were native to North America, were larger and easier to carve than turnips. This led to the practice of creating Jack-O’-Lanterns, now a big part of Halloween and used to ward off evil spirits.