- "There's always a bigger fish."
- ―Qui-Gon Jinn
The sando aqua monster was the largest carnivorous aquatic mammal living in the oceans of Naboo. Little was known about these giant creatures, and there were many myths and legends regarding their origins and habitats. What little was known about them terrified researchers as well as Naboo citizens and denizens across the galaxy.
The sando aqua monster had a long, sinewy body that was almost feline in appearance, with hind legs used for movement on the ocean floor and massive finned claws to propel it through the water. Lacking a layer of fat or blubber, it was poorly streamlined, and not fully adapted to swimming. Males could reach over 200 meters in length, with females being at least 150 meters in length. Being mammalian, females nursed their young for about a year. Females bore only one pup per birth. The average lifespan of a sando was thought to have been a hundred standard years, although their elusiveness made any accurate study difficult.
Their limbs were part flippers, part claws; scientists theorized that they had only recently evolved from land-based ancestors. Some believed the large, bulbous organ located toward the end of the sando's tail to be a possible remnant of life on land, though the exact function of the organ is unknown. There were even reports of sando monsters surfacing in swamp lakes and attacking falumpaset and fambaa herds, and unsubstantiated reports of them sunning themselves on sandbars. Unsurprisingly, scientists had never been close enough to observe their eating habits, and had never discovered how the beasts sustained their gargantuan bulk. The sando life cycle was a mystery, as they were dangerous, although reclusive, predators. To most natives of Naboo, sando aqua monsters were more of a myth than an actual creature, mainly because they had never been observed in the wild and reports of their washed-up carcasses were rare.
Reports of a sando's washed-up corpse were rare, though Lieutenant Quarsh Panaka of the Royal Naboo Security Forces encountered a beached sando youngster prior to the Invasion of Naboo. It had been attacked by two opee sea killers, and it had surfaced, revealing a secret facility run by a man nicknamed Veermok. The incident was later covered up, and the area destroyed.
While attempting to reach Theed during the Invasion of Naboo, Qui-Gon Jinn, Obi-Wan Kenobi, and Jar Jar Binks encountered a sando aqua monster in their Bongo. Kenobi was able to avoid the creature's maw, but an opee sea killer pursuing the submersible was not so fortunate, after clamping its jaws around the opee the giant beast stood on its legs and cracked the fish in half to feast upon it, giving the Jedi time to flee deeper into the planet's core. Soon after, they found themselves being pursued by an eel-like colo claw fish, but were again unexpectedly saved by the same sando when it caught and ate the claw fish.
- Jedi Academy: The Phantom Bully (Non-canonical mention)
- The Monster"—Star Wars Gamer 2 "
- Episode I Adventures 9: Rescue in the Core
- Episode I Adventures 10: Festival of Warriors (Mentioned only)
- Episode I Adventures 11: Pirates from Beyond the Sea (Mentioned only)
- Star Wars Episode I: The Phantom Menace novel (First appearance)
- Star Wars: Episode I The Phantom Menace
- Star Wars Episode I: The Phantom Menace comic
- Star Wars Episode I: The Phantom Menace game
- Star Wars Episode I: The Phantom Menace junior novel
- Episode I: Obi-Wan Kenobi (Appears in flashback(s))
- Star Wars: The Clone Wars – "Children of the Force" (Appears in hologram)
- Star Tours: The Adventures Continue
- Star Wars Episode IV: A New Hope junior novel (Mentioned only)
- Star Wars Episode I: The Phantom Menace (reference book) (Picture only)
- Star Wars: Episode I toy line
- Star Wars: Episode I Insider's Guide
- Star Wars: Episode I The Visual Dictionary
- The Wildlife of Star Wars: A Field Guide
- The Official Star Wars Fact File 25 (NAB4, Naboo)
- Coruscant and the Core Worlds
- The New Essential Guide to Alien Species
- "The Toughest Ever Creatures"—Star Wars Insider 102
- The Complete Star Wars Encyclopedia
- Star Wars: Head-to-Head Tag Teams
- Totally 20: The Phantom Menace
- Star Wars Character Encyclopedia