Rembrandt is a black rat. He has sleek black fur and long impressive whiskers. Rembrandt once belonged to Samuel Sparks, and being the art teacher, perhaps named the rat after the artist Rembrandt. After Samuel and his brother Ollie Sparks returned to Sparkling castle, Samuel gave Rembrandt to Billy Raven and Billy accepted, as to he loved the rat. Rembrandt also told jokes and Billy found Rembrandt as an animal friend next to Blessed. Runner Bean, Benjamin Brown's dog, always chases Rembrandt when he comes over to Benjamin's house. Later, when Billy is taken to Badlock, Rembrandt happened to be in Billy's pajama pocket, and caused trouble at Badlock, especially where Edgar Badlock, the enchanter's grandson was. (The enchanter and his wife Lilith were the only people to see rats in Badlock).