Subs Rock

Principal Celestia fills in as a substitute teacher, much to Twilight's excitement. Before she can begin her geology lesson, however, Miss Cheerilee calls her to the library. When she returns to the classroom, she tries to continue the lesson only for Granny Smith to appear and ask for help in the cafeteria. Upon returning a third time, Celestia is interrupted again by Rainbow Dash kicking a soccer ball against the outside of the classroom wall. The fourth time, the classroom telephone rings, and Celestia is called away to address an unspecified situation. Celestia returns once more, confident that was the final interruption, but the school bell rings and class ends, much to her disappointment.