Police received a number of complaints of a man man running through the parking lot of the Lucky supermarket around 4:25 a.m. Wednesday, the San Francisco Chronicle reported.
Witnesses described the man "not wearing pants or possibly just underpants and wearing a 'Scooby-Doo' or bear-type head mask," police said.
When officers Miguel Sanchez and Mike Gilfoy arrived at the scene they indeed found a man wearing a Scooby-Doo mask, along with a black leather dog collar and leash and khaki-colored pants.
When asked what he was doing, the man told officers that "he had recently lost weight and wanted to show off his new body," police said.
The man, whose name was not reported, was let go after the officers determined no crime had been committed.