Mary

The Walking Dead
Mary was a survivor of the zombie apocalypse and was the mother of Gareth. She was considered the matriarch of Terminus and was a cannibal like the others. She was shot in the leg when Carol Peletier came to Terminus to rescue Rick Grimes and his group. The injured Mary was attacked and infected by walkers. Gareth later mentioning coming upon her corpse, so it likely that he put her down either before or after she could reanimate.