Captain Bemoth (キャプテンベモス,Kyaputen Bemosu?) is a boss in Sonic and the Secret Rings. He appeared as the captain of a fleet of pirate ships that is being ravaged by storms (probably having been summoned by the Water Blue Ring).
He initially looked like an average Pirate Djinn until he fused with several Slime Djinn and transformed into a large leech-like creature with arms and a bearded face. He is mostly blue, with purple and green on various parts.
He is the one responsible for Sinbad the Sailor's capture and stole his World Ring to control the storms but instead ended up destroying a large portion of his own ships. Despite having no legs he can move very fast and create large waves of water, as well as generating electric shockwaves. He was defeated when Sonic pulled out his horns, which were his source of power. However, it is implied that Bemoth was not killed.
Captain Bemoth's attacks include swarming several bombs at Sonic and turning around to charge at him in a sort of tornado/whirlpool. Whenever he came close, Sonic would have to perform a homing attack on one of his horns, then pull the horn off. When he was latched on, the Captain would charge up a ball of electricity. If Sonic could not pull the horn off, the Captain would fill itself with electricity to attack Sonic. If Sonic could pull the horn off, the Captain would turn around and float backward while performing his final attack: powerful waves of water which Sonic would have to avoid. It was only during this wave attack that Sonic could pull off the Captain's final horn, causing him to roar in pain in his final breath. His defeat would give Sonic the Water Blue Ring of Pleasure.
The name Bemoth is probably derived from Behemoth, a Biblical creature. The word is commonly used to refer to any large or powerful entity.
Bemoth was the only boss in the whole game that was notkilled by Sonic, with the possible exception of Erazor Djinn.
It could be possible that Captain Bemoth is a Djinn, because Slime Djinns and a Kri Ma Djinn were used to create the monster.