The miridon sea monster was a large, green reptilian beast native to the oceans of Tarnoonga. It would frequently nest and swim about the various undersea mountain tops that broke the ocean's surface.
In 15 BBY, the pirate known as, Captain Gir Kybo Ren-Cha, used one of the mountain peaks as a base of operations. One of his favorite hobbies included forcing prisoners to walk the planks of his desert skiffs and watching them drop down into the sea–a snack for the miridon. Kybo believed that he had domesticated the creature and that it would actually respond to his commands, but this was merely a delusion of grandeur on Kybo's part.
On one such occasion, Kybo's men cast Jann Tosh and the droids, C-3PO and R2-D2 into the ocean depths in the hopes of watching them get devoured by the miridon. Thanks to R2's dome propeller extension however, they were able to avoid being eaten, and successfully trapped the animal inside the remains of a sunken freighter.
The miridon eventually escaped from this trap and returned to Captain Kybo's pirate cove in search of more morsels of food–the two-legged kind.
- Star Wars: Droids—"The Pirates of Tarnoonga" (First appearance)
- The Pirates of Tarnoonga: A Droid Adventure (Adaptation of "The Pirates of Tarnoonga")