Who Was The Dinosaur In Across The Spider-Verse? Spider-Rex Explained
"Spider-Man: Across the Spider-Verse" features a heaping ton of different Spider-People from across the multiverse — hundreds upon hundreds, in fact. However, few of them are as outlandish as Spider-Rex, a giant dinosaur who has a Spidey suit and (at least, presumably) fights crime when he's not hanging with the Spider-Society. The beast pursues Miles Morales (Shameik Moore) during his big chase midway through the movie and very nearly catches him with his giant jaws, making for yet another of the absolutely thrilling and absurd set pieces these movies have become known for.
As is the case with many of the other strangest Spider-People incarnations seen in "Spider-Man: Across the Spider-Verse," Spider-Rex actually comes from the original comic books that set the foundation for the movie. In fact, the character debuted in 2022, just one year prior to the release of "Spider-Man: Across the Spider-Verse." His true identity is Pter Ptarker (really), he hails from Earth-66, and his origin story is just as entertaining and bizarre as one would hope.
Pter Ptarker learns about dino-responsibility
Fittingly, Spider-Rex's first comic book appearance came in the first issue of the limited series "Edge of Spider-Verse" Vol. 2. In this issue, fans learned of Pter Ptarker's backstory, which essentially takes all the classic Spider-Man tropes and dinosaur-izes them. As the story goes, Pter Ptarker was originally a Pteranodon that was prey for the ultra-strong Norrannosaurman (that is a Norman Osborne analog, thanks for asking). Before he could be killed, however, the mortal enemies were both struck by meteor full of...alien spiders. Not only did the spiders give them superpowers, but it also miraculously switched their bodies, turning Pter Ptarker into the triumphant T-Rex he is today.
From there, Spider-Rex crossed over into the mainline "Spider-Man" comic book series, getting wrapped up in a multiverse-hopping Spidey-vs.-Spidey plot thanks to the machinations of Shathra. Now, he's made his animated debut in "Spider-Man: Across the Spider-Verse." Jury's still out on how big of a role he has in "Spider-Man: Beyond the Spider-Verse," though, if he has one at all.