Auction houses sell real estate, horses, cars, even full amusement parks including the roller coaster and carousels. But sometimes antiques and collectibles auctions can have the strangest things for sale. We have seen gallows, artificial legs, outhouses, fake mermaids, two-headed calves, and even an antique body preserved in a barrel of rum sold at auction. A March 1, 2017, sale at Bonhams in London had an item most have never seen. Lot 92 in a sale titled “Fine Books and Manuscripts” was a 2-inch glass disk in a black plastic rim. It was full of Penicillium chrysogenum, the mold used by Alexander Fleming when he discovered penicillin. Later, when penicillin had become famous, he made discs in his laboratory by growing some mold on blotting paper circles, fixing it with formaldehyde, and mounting it between two pieces of glass. He used tortoiseshell, gold or plastic for the rims on his “mold medallions.” Then he signed the backs of the medallions and gave them to important people, relatives, and as “thank-you” gifts. The Bonhams medallion sold for $14,617. In 1996, a disc sold to Pfizer, the pharmaceutical company, for £23,000, which is about $51,000 in today’s dollars.