There's a prequel to "How the Grinch Stole Christmas," and it's set at Halloween.

"Halloween is Grinch Night" was written by Dr. Seuss in 1977, 20 years after the book "How the Grinch Stole Christmas" was published.

The film won an Emmy for Outstanding Children's Program.

Thanks to its positive message and witty one-liners, "How the Grinch Stole Christmas" is a festive favorite.

However, not many people know that there's a prequel to the Dr. Seuss tale.

The prequel to the story is called "Halloween is Grinch Night," and it first aired as an animated TV special for Halloween in 1977.

You can watch it here:

Much like the Christmas tale, "Halloween is Grinch Night" tells the story of the Grinch terrorizing the Whos of Whoville — only this time his plot is foiled by a young boy named Euchariah Who, rather than Cindy Lou Who.

Dr. Seuss wrote the prequel 20 years after "How the Grinch Stole Christmas," which was published as a book in 1957.

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The Halloween story was so well received that it won the 1978 Primetime Emmy Award for Outstanding Children's Program.

The Grinch is no cheerier at Halloween than he is at Christmas. YouTube/Garry Foster

Dr. Seuss wrote another tale of the Grinch, "The Grinch Grinches the Cat in the Hat," which premiered as a TV special in May 1982 and also won an Emmy.

"How the Grinch Stole Christmas" was remade as a feature film in 2000, starring Jim Carrey as the Grinch. The latest adaptation of the story, "The Grinch," was released in November and is a 3D-animated feature film starring Benedict Cumberbatch as the voice of the Grinch.