The cat video had me tricked at first, then I saw the same moves repeated in reverse. Almost had me kitties. 

That dog looks kinda nasty with that girl, but helps her stay awake :p

And the shark video, I think that one guy at the end is totally wrong on what he thinks he saw. It looks far from the same thing and the mouth is not even the same. Hard to say what it is, but we know it is a carnivore and it is smart as caged food is easy food. I am really curious to know what it is. Perhaps it is not quite exoskeletal but something that has the same style jaw as a great white, except instead of being the upper jaw that lunges forward, perhaps its the lower one that does. That is what I am seeing. It looks like there is more movement with the mouth catching the prey rather than its entire body. So much is unknown in the under water world.  I think it is fascinating.