The extraordinary moment where hundreds of crabs protect a spy robot from one very hungry stingray. Spy in the Ocean is available on iPlayer in the UK and will be available on PBS in the US in the autumn. Subscribe: http://bit.ly/BBCEarthSub #BBCEarth #StingRay #Robots Watch more: Planet Earth http://bit.ly/PlanetEarthPlaylist Blue Planet http://bit.ly/BluePlanetPlaylist Planet Earth II http://bit.ly/PlanetEarthIIPlaylist Planet Dinosaur https://bit.ly/PlanetDinosaurPlaylist Welcome to BBC EARTH! The world is an amazing place full of stories, beauty and natural wonder. Here you'll find 50 years worth of entertaining and thought-provoking natural history content. Dramatic, rare, and exclusive, nature doesn't get more exciting than this. This is a commercial page from BBC Studios. Service information and feedback: http://bbcworldwide.com/vod-feedback--contact-details.aspx