Staff and customers ran for cover when the unusual visitor appeared at the doors of the Eurospar store in Carrickfergus on Saturday morning.
The shop manager told BBC News NI the stray goat charged at one of his regular customers, named Billy.
He said the goat “butted” Billy in the back before he managed to drag the pensioner into the shop for safety.
“We had to trail him inside,” the manager said, but added that the pensioner was not injured.
In the forecourt of the shop, the goat got up on its hind legs and jumped on two cars, one belonging to a customer and another to a staff member.