Octosacs are planet Mongo’s version of Earth’s Octopi, which in fact bear little or no variation from these vicious beasts aside from smaller size and less aggressiveness. Indeed, Octosacs have been known to menace Shark City and its inhabitants for centuries. Their eight multi-suckered tentacles are all extremely strong and, after confusing prey with a blast of ink, they will drag it into the beast’s maw.
A submarine carrying Flash Gordon and Dale Arden captive to Shark City was nearly attacked by one, in which case they would obviously have been sunk, had it not been distracted by a Shark. A single specimen had also previously been captured by the Shark Men’s leader, King Kala, and used to attack prisoners in the Chamber of Watery Doom. Flash was fighting it for his life and going to share this fate until Princess Aura and Prince Thun threatened Kala with a gun and made him drain it. Because also like Octopi, Octosacs need water.