Basilisk Leviathans were flying, territorial behemoths that put up a tough fight. They had a rapid-fire flame-spitting attack that was launched from a moderate distance, as well as an electrical, full body charge and a shock bubble drop that dispensed several bouncing balls of crackling energy, which zapped Ratchet on contact. Ratchet had to keep these foes in sight at all times, avoiding their attacks at all costs, and sending off a stream of continuous fire until there was nothing left but a few shards of Raritanium and a valuable Leviathan Soul.
In All 4 One A Basilisk Leviathan is seen to be in Cryosleep, it is unknown what it's purpose is for but it is only seen once in the game, it is likely that it was one of the creatures the Loki was planning to control before Ratchet, Clank, Qwark and Dr. Nefarious arrived on Magnus
Ratchet & Clank Future: Tools of Destruction
Ratchet & Clank: All 4 One
Stellar Leviathans were the ultimate evolution of the Leviathan species, being capable of taking on fighter ships in combat. They were to appear in A Crack in Time but were cut, though they could still be seen in the Insomniac Museum.
During development, the "spines" of the Basilisk Leviathan were removed to make them move better.