The turtles find April's long-lost mother frozen in a Kraang Stealth Ship buried under the farmhouse, though Mikey doesn't trust her and senses there's something wrong, he follows her into the woods where she's spilling a canister of mutagen, later it's revealed it's not really April's mom, it's an experimented clone with Mrs. O'Neil's memories. The creature is defeated by April with a psychic blast.Buried Secrets
The episode is inspired by films like John Carpenter’s The Thing as April’s mom turns out to be more than what she seems.
Both the Thing and Mom-Thing were found frozen and came from an alien spaceship.
Raphael calls the creature "Mom-Thing" as a nod to the movie title itself.
Many parts of the creature's body were taken directly from the Thing's various forms throughout the film.
The creature's tiny spikes pop out in a similar way to the spider legs that first appear in the film popping out of the Thing's dog form.
When Bennings is taken over by the Thing and stumbles on the snow as the imitation process is incomplete, he is seen with monster hands that seem to be similar to Mom-Thing's hands.
The long neck resembles the scene where the Thing busts through Norris' chest with a smaller weird version of his head.
The split head references the blood test scene, where Palmer is proven to be an imitation and the Thing splits its head in two, killing Windows.
The turtles faces being revealed coming out of it's body resembles the last scene where the Thing is revealed to have a dog coming out of it's guts.
The big red tentacle thing the creature uses to absorb Casey and Raph also appears in the film.
As the characters in the film did, Casey tries to fry the creature, though it didn't work this time.
The creature broke into the barn from the underground, as an homage to the Thing's last desperate attack in the film.
Her monster face bears a resemblance to the aliens from They Live!, another of John Carpenter's films.
"Mrs. O'Neil" acted similarly to Ross Rose from the 1980 horror film Mother's Day.
The quote "You made Mother very angry." is taken directly from Mother's Day.
Her true form also resembles several creatures from the Silent Hill video games.
The "One of us" chant used when Mrs. O'Neil's clone was trying to convince April to join them, was taken from Freaks, a 1932 horror film, where the characters chanted "Gooba-gobble, gooba-gobble. We accept her. One of us, one of us.".