Snopes.com has recently verified the phenomenon of dolphin bubble rings.  This video shows dolphins creating these bubble rings, which are essentially water vortices infused with air, and then playfully biting them or swimming through them.

For more information: http://www.snopes.com/photos/animals/dolphinrings.asp

Here is a great video of oceanographer David Gallo revealing the incredible color-changing capabilities of octopuses, cuttlefish, and squids.

For more information, visit: http://www.ted.com/index.php/talks/david_gallo_shows_underwater_astonishments.html