The suspect entered a store in the 3700-block Of North Harlem Avenue around 7 p.m. Thursday night. He showed a handgun and demanded cash.
The man was wearing a red and blue Spider-Man mask, a hooded sweatshirt and dark pants.
On Tuesday, a man wearing a similar mask robbed a 7-Eleven store in the 2700-block of North Harlem in the Montclare neighborhood.