Investigators said it happened just after 1 p.m. at the Eagleson Residence Hall. The man showed a gun, but fled without getting any money.
The suspect was described as a black male wearing a white T-shirt with faded blue shorts. He was reportedly armed with a .38 revolver and had dreads.
The campus was placed on lockdown as police searched for the man. Students were told to stay in their rooms with doors and windows locked.
During the lockdown, there was report of a gunman in the Mary Townes Science Complex, but police said that turned out to be a false sighting.
The lockdown was lifted just before 3 p.m.