The ostracod is a tiny organism that emits a bio-luminescent chemical when eaten by a fish to make the fish visible to predators, which is why the fish in this gif immediately spits it out.

http://i.imgur.com/lW98uHV.gifv via /r/woahdude https://www.reddit.com/r/woahdude/comments/56sgch/the_ostracod_is_a_tiny_organism_that_emits_a/?utm_source=ifttt