What sounds like the beginning of a joke - a man walked into a liquor store with a pony - was not funny for a Rhode Island liquor store.

Police were called to Patriot Wine and Spirits in Warren, R.I., Monday after a man brought a Shetland pony into the store and, after a few laps around the store, the pony left a mess.

"He just walked in off the street with a pony, walked around the store for a little bit and, as they were leaving, the pony left a surprise," store manager Brian Mancieri told ABCNews.com.

When the pony's owner, identified by police as William Saviano, 51, refused to clean up the mess and left the store, a Patriot employee called police. Authorities tracked Saviano down about two blocks away and brought him back to the store where he was told to clean up the mess or face property damage charges, according to Warren Police Lt. Ronald Brule.

Saviano cleaned up the mess and no charges were filed. He told police he owns a horse and pony farm in Rehoboth, Mass., and had brought the pony to Warren for a children's party.

Mancieri says Saviano came to the store with a friend and that employees of the store, which is big enough to house a pony, did not notice his arrival at first.

"He kind of just walked in before anybody could pay attention to what he was doing," Mancieri said.

"We've had people bring in animals - birds, dogs, cats, even snakes - all the time," he said. "We've had incidents where the pets leave a mess, but they [pet owners] clean it because they know better. This guy just didn't because he was being rude."

After the pony's surprise visit, a store employee hung a sign outside the store reading, "No Horses Allowed." Mancieri says the sign has since been removed from the store's front but now hangs inside the store.