Carving jack o' lanterns began in Ireland hundreds of years ago because of the myth of "Stingy Jack".
According to legend, Stingy Jack had a round of beverages with the Devil but he didn't want to pay, so he talked the Devil into turning himself into a coin so Jack could pay the barkeeper. But instead of paying for the drinks, Jack put the Devil Coin in his pocket next to a silver cross. This kept the Devil from changing back. Of course the Devil was not happy about this, so Jack made a deal with him. Don't bother Jack for a year, and if Jack died....the devil could not claim his soul.
A year later, Jack convinced the Devil to climb a tree to pick some fruit, then Jack carved a cross in the tree's trunk - trapping the Devil. Again, Jack made a deal. Don't bother him for 10 years this time. However, Jack died before the 10 years was up and God would not let someone such as Jack into heaven. And the Devil kept his word and did not take him into Hell. Instead, the Devil sent Jack off to roam with only a burning coal to light his way. Jack put the coal in a turnip that he carved and has been roaming ever since.
The Irish referred to the wandering Jack as "Jack of the Lantern".
After that...people in Scotland & Ireland began to carve faces into turnips or potatoes and displaying them in windows or near doors to scary Stingy Jack and other evil spirits away. In England, they used beets. Immigrants brought the custom with them to the US, and here they discovered that pumpkins make very nice jack o' lanterns!
Unlike these specimens that scare away more than just evil spirits!
Apparently they weren't made to last until November 8!