Amy (Emma Bell): The younger sister of Andrea (Laurie Holden) lost her life in Season 1 when a pack of Walkers overran their camp just outside of Atlanta. She was the first unsuspecting victim of the attack, which took place while the survivors feasted with their guard down.
Zombie Amy came back for a few moments after her heart-broken sister held her dead body in her arms all night, and waited to put a bullet in her head until she tried to attack.
Sophia (Madison Lintz): The daughter of Carol (Melissa McBride) was one of the most emotional losses for the "Walking Dead." The tight-knight group spent several Season 2 episodes searching for her after she went missing in the woods, before the group settled on the farm.
Zombie Sophia emerged, much to her mother's dismay, from the barn in which Hershel (Scott Wilson) had locked a number of other walkers. Rick (Andrew Lincoln) stepped up to the plate to put a bullet in her head.
Randall (Michael Zegen): This young man had a rough run with Rick and company after being taken prisoner when his rival allies left him for dead in Season 2. After a looooong debate about whether he should live or die, Shane (Jon Bernthal) snapped his neck in the woods.
Zombie Randall attacked Glenn (Steven Yeun) and Daryl (Norman Reedus), who discovered he had no bite marks -- leading them to realize he was murdered, and that every human left on Earth carries the zombie virus.
Shane (Jon Bernthal): Once Rick's best friend, he shacked up with Rick's wife Lori (Sarah Wayne Callies) after the apocalypse, only to be ditched when Rick returned. The tension between the three characters culminated in...
Zombie Shane's rise from the dead after he tried and failed to kill Rick. With one shot, Rick's son Carl (Chandler Riggs) snuffed out Zombie Shane and his own childhood.
Merle Dixon (Michael Rooker): The brother of fan favorite protagonist Daryl lost his hand in the first season after the group left the aggressive racist handcuffed to a zombie-infested roof. He re-emerged in Season 3 as one of The Governor's most ruthless agents, and eventually tried assassinate him.
Zombie Merle made an appearance after a rocky reunion with his brother and the rest of the group -- only to be put down by his brother.
Milton Mamet (Dallas Roberts): The Governor's quiet and intelligent, yet naive right-hand man emerged in Season 3 when Andrea and Michonne (Danai Gurira) stumbled upon safe haven Woodbury. He wanted to believe that the walking dead maintained memories of the living.
Zombie Milton rises after being killed by The Governor upon refusing to kill Andrea in the Season 3 finale. While his corpse is locked in a room with Andrea, he re-animates and chomps into her neck before Rick can come to her rescue.
Lori Grimes (Sarah Wayne Callies): Rick's wife and Carl's mother manages to give birth to her second child as zombies invade the prison, but dies during the C-section delivery. Carl has the unpleasant task of putting a bullet through her head to ensure she stays dead.
Zombie Sarah was not seen on television, but rather a deleted scene in which Rick imagines kissing her one last time -- only to open his eyes to see he was making out with a gruesome zombified version of his wife.