who was feeding the rats to the walkers
Lizzie and Mika Samuels Lizzie's psychotic behavior and Mika's innocence are addressed in the second half of the season, with the revelation that Lizzie was feeding rats to the walkers at the prison. Most notably during "The Grove" episode, Lizzie murders Mika, and intends to allow her to reanimate. Having found this out, and knowing that she also planned to kill Rick's daughter, Carol made the decision to kill Lizzie. The scene sparked controversy among critics, who continue to refer to it as one of the darkest scenes and episodes of the series.