First heard of this one in the Wii game Endless Ocean (cuz I love the fishies) and finally got brave enough to explore The ABYSS (wtf is with the scary-ass drama-llama music?).
BEHOLD! The Amazing Exploding Jelly-Thing!
The Praya Dubia, or Giant siphonophore, can reach up to 40-50 m (131-164 ft). They're found in deep sea, and go all esplodey when taken out of their natural home - which is pressurized at about 0,47 tons/cm2. AND? They glow.
Wiki Link: http://en.wikipedia.org/wiki/Praya_dubia
The University of California Santa Barbara: http://www.lifesci.ucsb.edu/~biolum/organism/pictures/praya.html
