Ms. Grunion (voiced by Allison Janney) is the main antagonist of Mr. Peabody and Sherman. She doesn't like Mr. Peabody, who was raising Sherman, and wanted to do anything she could to get him away from the boy. Her plans failed, and was defeated when she was grabbed by Agamemon, and brought back with him to his respected time. This, however, was actually a good thing to happen to her as both Agamemon, and herself get married while in the Trojan Horse.
