According to Linus van Pelt, the Great Pumpkin is a Santa-like figure who comes to the pumpkin patch on Halloween to bring toys to the most sincere children. Linus sits in the pumpkin patch every Halloween, earnestly awaiting the Great Pumpkin's arrival. Every Halloween, he is disappointed, but hopeful for the next year.
The holey spirit is Charlie Brown's Halloween costume. Typically, Lucy dresses as a witch and the rest of the children go as ghosts wearing sheets with eye holes cut out. Invariably, Charlie Brown has trouble with his scissors and arrives with more eyes than Ezekiel's cherubim.
The question about if the holey spirit will ever leave the earth is based on a misrepresentation of the Great Pumpkin. He leaves toys for the most believing child; he does not take away the child with the worst costume. Unlike the
Holy Spirit, who is here and won't leave even during the Tribulation, there's no indication that the Great Pumpkin is actually real, let alone ever showed up in a pumpkin patch.