Infantata

Thaddeus Montgomery (aka Infantata) is a being crafted from the pieced together remains of Charles and Nora Montgomery's child, Thaddeus. He is a character in the first season of American Horror Story. primarily portrayed by Benjamin Woolf. Though never referred to as "Infantata" or "the Infantata" in the dialogue of the series, this name has been given as the creature once known as Thaddeus by the credits and by members of the series' production during interviews.

Past
Charles performed abortions in the basement of the house in the 1920s to alleviate his family's financial distress. Unfortunately, one of his patients told her boyfriend, who kidnapped Thaddeus and dismembered him in an act of revenge. After the pieces were returned to Dr Montgomery in jars, he lost his mind and attempted to sew his son back together, bringing Thaddeus back to life. To achieve this, he told Nora he used "the beating heart of one of our girls", presumably referring to an almost fully developed fetus he removed from one of the patients.

When Nora tried to nurse the reanimated Thaddeus, it bit her to quench its blood thirst. She then, realizing the truth of what her son had become, tried to kill it with a letter opener, but claimed that it wouldn't die. Nora would later kill Charles and herself over his crime and what it had forced her to do. The Infantata continues its existence in the basement, slaking its blood thirst.

Infantata once attacked Tate when he was a young boy. Nora rescued him and told him it would disappear if he closed his eyes and told it to go away, which began her motherly relationship with Tate.