Liopleurodon リオプレウロドン

Created in the early stages of Godzilla: Tokyo S.O.S. (2003), Liopleurodon was intended to be the unfortunate victim of Godzilla, its giant body washed up on the shores of Kujuukuri Beach, carrying on its body the fatal scars of a battle with the nuclear menace.

As development continued, it was decided that the massive plesiosaur should instead have its role given to a monster from Toho's library. Anguirus was intended to fill the role at first, but Toho staff became reluctant as it was thought having such a popular monster relegated to a corpse wouldn't sit well with audiences, thus leading to the torch being passed to the more obscure Kamoebas from Space Amoeba (1970).

• The featured concept artwork and name of the monster can be found in the 2016 book Shinji Nishikawa: Drawing Book of Godzilla (ISBN: 480030959X) and in Godzilla X Mechagodzilla X Mothra: Tokyo S.O.S. Fantastic Collection. The latter book also notes the order for which monsters were considered to be the corpse on the beach (Liopleurodon in the preparation draft, followed by Anguirus, then finally Kamoebas).
• One common nickname for the monster and popularized by fans is "Giant Mosasaur".