SPOKANE, Wash. -

The park bench stackers hit Spokane parks three times in August and apparently struck again.

On Christmas Eve about 30 park tables were stacked in Riverfront Park. By Christmas morning, however, the pyramid had been knocked down.

City employees say some of the tables were damaged by the overnight prank.

Back in August, the city had to use a forklift to undo a similar prank. While it may seem like a harmless joke, the Spokane the parks department said it costs about $500 to take the benches down one by one.