The Monroe County Sheriff's Office said Eli Escalera, 43, was wearing the shorts like a hat Friday when he walked into the First State Bank on Stock Island near Key West at 12:30 p.m. and handed a note to a teller reading, "Give me what are 20s and 50s," KeysNet.com reported Monday.
The confused teller asked Escalera what he wanted and he responded by saying "nevermind" and leaving the bank, investigators said.
The bank manager called authorities and Deputy Matt Dowling spotted Escalera on a nearby street. The suspect attempted to flee on a bicycle, but was quickly apprehended, authorities said.
The sheriff's office said investigators do not know why Escalera was wearing shorts on his head.