paragraph: You can think about static electricity like a teeter-totter. Things are fine as long as they are balanced. The same can be said about electrons. Too many or too few can be shocking! Static electricity is all about that balance. Charges can build up through friction. Some materials freely give away electrons. Other items easily gain electrons. Have you ever rubbed your feet on a wool mat or carpet? Rubber soled shoes readily accept electrons. The wool carpet easily gives up electrons to the shoes. This combination provides for a large transfer of electrons. This buildup of electric charges is known as static electricity. Positive charges build up on the mat and negative charges build up on you. What happens when an object becomes charged? A material is likely to remain charged until it touches another object. Sometimes it will discharge if you just come close to another object. What comes next may be shocking. 
question: What happens when an object becomes charged?
answer: It causes energy