It happened on December 9 at the Pet Smart Store located on the 4600 block of Roosevelt Boulevard.
Police say the suspect entered the store at 10:30 a m., approached the counter and pulled a handgun from his waistband.
VIDEO: Click here to watch the surveillance video
When the female employee told him she could not open the cash register drawer, the would-be robber said he was "just kidding" and fled the scene.
Nothing was taken and no injuries were reported.
The suspect is described as a black male, 40 years-old, 5'10" tall, 200 lbs with a goatee. He was wearing a blue and gray hooded sweatshirt with Dickies written on the front, camouflage pants, black boots and a dark colored cap.
Anyone with information is asked to contact police at 215.686.TIPS (8477) or text a tip to PPD TIP (773847).