Magical organism of the sea

Ocean magic. These huge colonies of organisms filter water to consume plankton. They can be as long as a whale and as wide as 6 feet, but according to some scientists you wouldn't want to get inside one, they look like a Chinese finger trap. One group of scientists found a dead penguin inside who couldn't maneuver front or back and so was stuck. Added bonus, they glow in the dark (bioluminescent). Makes me want to dive.