Rerun is Linus and Lucy's younger brother. Rerun is often embarrassed by his older siblings, telling people he has no other brother or sister. Lucy is annoyed by his constant ramblings and throws him outside often. He desperately wants a dog, but his mother tells him no. In I Want A Dog For Christmas, Charlie Brown, Rerun tries his hand at taking care of Spike, Snoopy's brother. He finds it's more than he can handle. He also hates going with his mother on the back of her bike, as she is a terrible driver and crashes into things all the time.