Ms. Grunion

Ms. Grunion is the main antagonist of Mr. Peabody & Sherman. She is a bigoted social worker from the Bureau of Child Safety and Protection and Mr. Peabody's archenemy. She's voiced by Allison Janney.

Role in the film
Ms. Grunion first appeared when she was notified by Principal Purdy that Mr. Peabody's adopted son, Sherman, had gotten into a fight with a classmate, Penny Peterson, during which he had bitten her. Ms. Grunion dismissed the fact that Penny had started the confrontation and instead accused Mr. Peabody of failing to be a suitable parent, and informed him that she would conduct an investigation of his home, threatening to remove Sherman from Mr. Peabody's custody lest she find evidence that Sherman wasn't being raised properly.

Ms. Grunion later arrived at Mr. Peabody's apartment for the investigation, unaware that Mr. Peabody and Sherman had created a time paradox, which had resulted in cosmic doubles of Peabody and Sherman being created. After Mr. Peabody failed to hypnotize Grunion, she discovered the second Sherman and used this as evidence of bad parenting on Mr. Peabody's part. Ms. Grunion then seized both Sherman's and began to drag them away, but the two collided, causing a rift in the space-time continuum. Both Mr. Peabody's attempted to remove the two boys, but all four of them combined, disrupting the space-time continuum.

In spite of what had transpired, Ms. Grunion made a second attempt to claim Sherman, but Mr. Peabody bit her, shocking everyone present. After getting over her initial surprise, Ms. Grunion phoned the police to report the bite. Panicking, Mr. Peabody, Sherman, and Penny fled to Mr. Peabody's time machine, the WABAC, and attempted to travel back to their correct time periods. Ms. Grunion, the Petersons, and the police attempted to pursue, but failed to stop the three from flying off. However, the WABAC was unable to travel to the past and a vortex opened in the sky, resulting in historical figures being unleashed upon the present. As Ms. Grunion pursued the WABAC, she briefly encountered King Agamemnon, who became smitten with her. However, she ignored him and continued after the WABAC.

After the WABAC crashed into the center of the city, Ms. Grunion ordered the authorities to seize Mr. Peabody to place him in the pound. However, Sherman stood up for Mr. Peabody, inspiring the citizens present to take a stand against Ms. Grunion. However, she pointed out that Mr. Peabody would still have to be locked up as he bit her. In response to this, George Washington, Abraham Lincoln, and Bill Clinton award Mr. Peabody a presidential pardon, much to Ms. Grunion's anger. However, the vortex began to enlarge, and the sphinx emerged from the vortex. Ms. Grunion was crushed under the sphinx's nose after it detached. She remain trapped under the nose until Mr. Peabody and Sherman reversed the space-time continuum via travelling to the future. Upon being freed, Ms. Grunion swore vengeance against Mr. Peabody, but was unexpectedly seized by Agamemnon and dragged back into his time period along with him.

Once in Agamemnon's time period, Ms. Grunion appeared to have accepted this and happily married him.

Trivia

 * It is possible Grunion was killed, as according to Greek mythology, Agamemnon's first wife murdered him and his new wife out of envy.