He's gonna get you!

William decided to head butt Charles tonight.  Instead of getting upset, Charles turned over on all fours, let out a war cry, and started barrelling at William.  He took off after him ready to attack.  William ran half shrieking, half laughing from the room to get away from the baby.  Thus, a game was started.  When Charles was rounded up and returned to the room, William came back in and head butted him to the floor once more.  Charles scrambled to his knees, let out his war cry, and the chase was on again.  William only laughed this time, and Charles was grinning the whole time he was tearing after him.