Rumor is that the giant creature or spaceship that chases Iron Man at the end of the new Avengers trailer went by the name Leviathan in the Avengers script. Whether that was just a codename or meant to be the actual name of the creature or ship is unknown. One theory we already wrote about is that the creature could actually be Fin Fang Foom, a dragon-like alien who has squared off against Iron Man in the past.
But there are also a lot of other possibilities. If the creature is actually called the Leviathan, then there are some creatures that have gone by that name in the comic books. Way back in Prince Namor the Sub-Mariner #3 there was a creature called the Levithan that was unleashed by Plant-Man. Of course this particularly Leviathan doesn’t really look like the creature in the movie, so we doubt it’s the same Leviathan.
Now, there was also a later creature called the Leviathan that actually fought the Avengers. Marrina, who was at one time Sub-Mariner’s girlfriend, morphed into a sea creature called the Leviathan. This Leviathan looks striking similar to the creature appearing in The Avengers trailer. It would also go along with all the Atlantis rumors, and it might help to explain why Iron Man is seen flying up out of the water in an early trailer.
While not matching up with the name Leviathan, another possible theory revolves around the Annihilation Wave. It’s already been observed that some shots of the smaller aliens make it look like they have an insect-like appearance, which had speculation revolving around Annihilus. If the object chasing Iron Man is a ship, then it certainly looks similar to these ships from the Annihilation Wave.
Yet another theory is that the Leviathan could have nothing to do with a sea creature or aliens. Maybe, the Leviathan and all of Loki’s army are just beings from the nine realms. Could the Leviathan just be the Midgard Serpent decked out in some type of hi-tech battle armor?