Over the past few months, odd floating jellies have been washing up on Pacific US beaches by the thousands. With clear plastic-like sails, and bright blue flesh, these harmless jellies have stumped many a beachcomber. Now, Steve Haddock and Susan von Thun of the Monterey Bay Aquarium Research Institute have put together a video explaining exactly what these creatures are, and their bizarre upside-down world:

For more info, check out http://jellywatch.org/velella