"The computer works great and may also be haunted by a ghost or specter," the seller "wfatzinger" wrote in the description, adding that it is not, however, "haunted by a demon or 'devil man' negative entity."
The seller wrote he thought the laptop became haunted because he forgot it overnight under a full moon in a graveyard where he was drawing sketches next to an abandoned mental hospital. He went back and found it propped open still playing a Beethoven song he liked, but then things started to get weird, he said.
"First I noticed that ALL of my songs in iTunes had become scary or haunted," the seller wrote. "Second, the desktop background was changed to a scary photo."
The seller and his wife Barbie noticed stuff around their house had been mysteriously rearranged while they were out the following week, he wrote.
"When we came home, my baseball cards were all out of order, and my wife's rare American coins were in total disarray," he said. "To make matters spookier, I occasionally saw the computer levitating."
Soon, the computer began to compose messages, the seller said.
"The way he communicates with us is by grasping a pen between the keyboard and monitor and writing on pieces of printer paper from our home office," he wrote. "As such, I am given to believe that this ghost may have lived in a time before computers, for he appears to be quite unaware of the purpose of the machine he inhabits."
When the seller took the laptop to the computer store, he said the "so-called 'geniuses' were unable to help him, and he was escorted off the premises by a security guard.
He then took the MacBook to a psychic medium, who placed the "haunted" laptop in the center of her table, held the seller's hands and performed some ritual that caused the lights to flicker, he said.
She believed the computer was haunted, he wrote, adding that she told him to burn incense around the computer before bedtime and sing to it.
"It sounds weird, but this seemed to help at least pacify the tormented soul," the seller wrote. "The computer remains haunted, but he became more peaceful and even helpful at times."
The seller said the MacBook also vacuumed the den and even wrote a note telling the seller it loved him.
"Whether he was giving me a hand cleaning the garage, helping my son (Thames) perform a rap song at a middle school talent show, or acting as a crucial sounding board when Barb and I had that rough patch last autumn, this ghost has been a rock solid friend and constant companion," the seller wrote.
And despite all this, the seller said he still wants to sell it because the family needs to clear space around the house.
"Sorry, but the unit is missing the power cord and I no longer have the OS X CD," he wrote. "Seller takes no responsibility for consequences of ghost-related haunting, negative or positive."
The seller, eBay and Apple did not respond to a request for comment by ABC News.