San Francisco police are asking the public to keep an eye out for an eyeball wearing a white top hat.
The eyeball is actually a mask, and it's quite valuable, estimated to be worth $100,000.
Some fans of avant-garde music might have seen the giant eyeball on members of the Residents, a San Francisco-based musical act known for its multimedia works, and of course, their costumes.
Now the one of the four eyeballs featured prominently on the band's albums has been stolen.
San Francisco police say the owner of the mask loaned it to a museum in Seattle -- as it has been in the past and around the country. A museum curator shipped the mask back to the owner on May 5.
But the owner, a San Francisco resident, was out of town when the package arrived. Police said someone with an illegible signature signed for it, and like that, the eyeball was gone.
Also stolen was the original album cover photo, valued at $20,000.
Police and the owner are now hoping someone has seen the massive eyeball.
Anyone with information about the stolen eyeball and photo is urged to call an anonymous tip line at (415) 575-4444 or text a tip to TIP411 and include "SFPD" in the beginning of the message.