
Charleston Bump Expedition 2003. NOAA Office of Ocean Exploration
Facebook user Jr Saim posted a video of the writhing animal on Sept. 28 after he caught it off the coast of Changi, Singapore. He adds that he later released it.
It turns out the strange creature is actually a basket star, a member of the same phylum, Echinodermata, as sea stars and sand dollars. Basket stars are a type of brittle star, creatures that are known for their slender, spiky arms - although the basket star takes its appendages to a whole new level.

Jr Saim
Basket stars are capable of living very deep under the sea - up to 6,000 feet or so - and feed mainly on tiny animals called zooplankton.
Here's another, less wrigly image of the basket star:

Derek Keats/Flickr