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 (dubbed by fans "Murder House") 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.
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.
Pilot - In a flashback to 1978, Infantata kills the trespassing twin boys, Troy and Bryan. In the present time, Infantata, along with Tate, scares Leah to stop her from harassing Violet at school.
Murder House - Thaddeus Montgomery appears as human, sitting at the table.
Open House - Thaddeus' name is given and origins are elaborated on.
Birth - A flashback to 1984, shows Tate was attacked by the Infantata as a child. Nora saved him and taught him how to make entities in the house disappear in case it ever happened again.
To Leah: "Mommy...?"
He is the first character inspired by Frankenstein in the American Horror Story series, the second is Kyle Spencer.
Concerning Infantata's design, Ryan Murphy states that the mouth is based off of a leech mouth. The character's overall "look" is inspired by the genetic disease Progeria, and the character's clothing is inspired by one worn by the Lindbergh Baby.
Ryan Murphy has said that Infantata is not a ghost, but a still-living creature that has been eating possums and bugs to sustain himself, and that he typically does not leave his hole in the basement unless provoked. Despite Infantata being alive the phrase "Go Away" apparently still works in keeping him at bay.
Ryan Murphy on the Infantata
Entertainment Weekly: "I love the infantata flashback. Love that his name is Thaddeus. Why is he bloodthirsty? Is that to keep him alive?
" Ryan Murphy: "Yes. I think with any sort of horror show, you get what is the myth of that creature? And I think the approach we took to that is it’s sort of half-Frankenstein, half-Dracula. Left by himself in the house. Bloodthirsty. We’ve shown in other episodes where he’s been eating possums and bugs to sustain himself.
"Entertainment Weekly: "Is the Infantata still alive?
" Ryan Murphy: "He’s down there scavenging for bugs and eating possums until some other poor souls go down there.