Demand to see a manger and when you see him get all mad and yell at them that you know of the stores plot to take over the world by brainwashing people with their electronics and the drugs that they are putting in the food. Then say it will not be tolerated and then run off, knock over as many displays as you can and make the employees chase you though the store.
Move all the shelves to the walls and take oil or gas and spill it on the floor shaped into a pentagram and light it up with fire then ride a pink bike around it.