"Jack O'Lantern" is a Halloween-themed episode of the American animated TV series Festival of Family Classics, which was produced and directed by Arthur Rankin, Jr. and Jules Bass. The episode first aired in the United States in syndication on October 29, 1972. Although the majority of episodes of Festival of Family Classics are based on famous novels, poems or folktales, "Jack O'Lantern" is an original story written by William J. Keenan. It bears hardly any resemblance to the traditional tale of Stingy Jack.
The episode's title character is an Irish leprechaun who takes on the form of a pumpkin in order to enjoy a long sleep. Jack O'Lantern is awakened when a boy carves a face into the pumpkin in order to make a head for a scarecrow. Jack explains to the boy and his sister that the reason why their father is unable to grow any crops on his farm is because the farm is being magically attacked each night by a witch and her husband. Jack offers to use his superior magical powers to protect the farm.
An old man named Michael is visited on his farm by his young grandson and granddaughter. The two children want their grandfather to tell them a story, one that they have obviously heard before, about the jack-o-lantern on Michael's windowsill.
As a boy, Michael and his sister Colleen move with their father from the city to a farm. They have a horse named Swayback, a cow named Lulu and a goat named Billy. Although the children's father works hard, he does not succeed in growing any crops. He complains that crows eat all the seeds. Colleen points out that crows have not come to the farm since Michael made a scarecrow. The children's father says that, in that case, the problem must be caused by ghosts and goblins because neither he nor any of the neighboring farmers are managing to grow anything.
Michael thinks that things might get better if he improves his scarecrow, which does not even have a head. He asks Colleen to bring a pumpkin which she found to him in the barn. There, Michael carves a face into the pumpkin. When Michael finishes carving the pumpkin, it starts to glow. A voice speaking in an Irish accent then comes out of the pumpkin. The voice asks who carved holes into the pumpkin. Michael admits that he did it and apologizes to the pumpkin. The voice says that he is really a leprechaun named Jack O'Lantern. He took on the form of a pumpkin seed, which later grew into a pumpkin, in order to hibernate. Jack O'Lantern likes the fact that the two children are named Michael and Colleen because those names remind him of his native Ireland.
Jack appears to enjoy the idea of being a scarecrow. He explains to the children, however, that crows are not the reason why their father's farm is not prospering. Jack tells the children that their father's farm and all the neighboring farms are being magically attacked each night by Zelda the witch, her husband Sir Archibald the warlock and the ghosts, goblins and ghouls that Zelda commands. Zelda wants to drive all the farmers away so that she can take their land. Jack goes on to explain that the pot of gold which he keeps with him in his pumpkin shell gives him greater magical power than any ghost or witch. He tells the children to meet him in the field at midnight to see him protect the farm from Zelda and her minions.
Shortly before midnight, the children go out to the field. Jack says that Zelda and her associates will soon be coming. He tells the children that they do not need to be afraid. Jack says that as long as he has his pot of gold, he will be able to defeat Zelda every time. Zelda and the British-accented Sir Archibald arrive, both flying on broomsticks. Zelda calls on some demons to send down a hailstorm. Jack catches all of the hailstones in a horn of plenty. He blows into the horn and sends all of the hailstones flying back up into the sky, where they hit Zelda, Sir Archibald and the demons. Zelda starts a brush fire. Jack conjures up a tropical storm which puts out the fire immediately. Zelda calls on the demons to frost the soil. Jack borrows some of the midnight sun from the North Pole. The frost goes, leaving the fields watered.
Zelda realizes that the farm is being protected by the powerful leprechaun Jack O'Lantern, who has pulled the midnight sun trick on her before. She also notices a weakness Jack has that she can exploit. Jack is obviously fond of the two children. Sir Archibald does not want to involve the children, saying that they are likely to "botch things up". Zelda, however, says that nothing can go wrong this time. She tells the demons to create a diversion by attacking Jack O'Lantern and tells Sir Archibald to take the two children. When the demons start coming towards him, Jack tells the children to hide behind a haystack. Sir Archibald reluctantly abducts the two children, telling them that he is not enjoying it any more than they are.
After Jack has fought off the demons, Zelda shows him that she has Michael and Colleen tied up in a rope. She threatens to turn the children into stone unless Jack gives her his pot of gold by coming out of his pumpkin shell and leaving the pot of gold inside it. Jack emerges from the pumpkin shell in his true leprechaun form. He goes into the barn with Michael and Colleen. Jack and the two children are tied to a post. Zelda gives the pumpkin to Sir Archibald. She leaves with her demons to cast more wicked spells on more farms.
Lulu the cow, Swayback the horse and Billy the goat want to help Michael and Colleen. Jack has an idea. He shakes off his hat and then asks Sir Archibald to fetch it for him. When Sir Archibald bends down to pick up the hat. Billy the goat butts him, causing Sir Archibald to go flying through the air. Sir Archibald's head breaks through the wooden barn door and he gets stuck there. Swayback the horse puts a collar around the warlock's neck to help keep him in place, although he somehow manages to escape soon afterwards. Lulu the cow bites through the ropes which tied up Michael, Colleen and Jack to free them.
Jack goes back inside the pumpkin shell which contains his magical pot of gold. Without his scarecrow body, Jack flies into the sky in his pumpkin shell. Zelda and the demons use their magic to attack the farm again. Jack fights Zelda, Sir Archibald and the demons again and defeats them.
Although Michael and Colleen are very grateful to Jack for his help, Colleen points out that, due to Zelda's magic, the crops are still ruined. Jack says that he is now 6,000 years old and would like to retire. He says that if the children provide him and his pumpkin shell with a nice, warm, peaceful home, he will guarantee them a bumper crop. Michael tells Jack that he can stay with them forever. Jack scatters gold coins from his pot of gold on the fields. Crops grow instantly. Michael says that Jack has been with him ever since.
Michael's two grandchildren love the story, although they say that they do not believe it is true. The jack-o-lantern on Michael's windowsill then begins to talk in an Irish accent, saying that the story is true and that children should not accuse their elders of lying.