Shelley is actually Toshiaki's dead turtle, Shelley. Shelley is the climax antagonist of the movie. When he digs it up to use Victor Frankenstein's reanimation secrets on it, the experiment goes bad and the resurrected turtle grows to an extremely tremendous size. he died when Victor shocked him with two wires when his foot was in a puddle of water in the Town Square, in order to save Toshiaki. Turtlezilla is like Godzilla
- Unlike the other monsters, which were meant to reflect the classic Universal Studios movie monsters, Shelley was meant to resemble Gamera , a Japanese kaiju monster by Kadokawa Pictures . References also allude to those of classic pop culture monster Godzilla, rival monster of Gamera.
- In this movie, the Turtle Monster is voiced by Dee Bradley Baker.
- It's possible Shelly's name is a reference to Mary Shelley, the author of "Frankenstein", on which both the short film and 2012 film are based.
- The reason why Shelly grew to this size because of the miracle grow in toshaki's backyard while being re-animated by Toshiaki
- The Monster Turtle resembles a Tyrannosaurus Rex, king of the dinosaurs
- He ate some Sea Creatures that were on the phone booth where Mr. and Mrs. Frankenstien were in. He may have accidently saved them.
- The third film in the Frankenweenie frankensize is named after him.