© KVOA
He's had it for 25 years but still doesn't know what it is. It weighs nearly 20 pounds and measures about 10 inches in diameter.
In 1983, Kidd found "the thing" as he calls it serving as a door stop in a home he bought in Tombstone.
It's been chiseled for testing but geologists can't give Kidd an answer. He has an idea though, "People ask me what it is, I think it's a petrified miniature UFO," he said with a laugh.
He has letters from experts but no answers; even e-mails from people who think they have a similar one, "An old miner in tombstone told me he thought it was a big gold nugget inside that thing."
But Kidd, 82, won't dare crack the mystery, "I don't want to destroy something from the past there's too much of that going on right now."
So he'll wait for answers, meantime one thing is for sure, "Before I die I'd like to find out," he said.
looks like a giant fungi to me...either a mushroom cap or possible conk like grows on the side of trees