If the crabs are taking after the rats and this whole video is just a performance piece, I'm going to be pretty annoyed. When "Selfie Rat" proved to be a phony, I fell apart. As a result, I'm skeptical of any animal doing anything cool. Still, I'd sill love to believe that this crab holding a kitchen knife is as real as it gets.
This past week a video went viral featuring a cab running away and warding off the dude filming this video with a kitchen knife. While on their own crabs can be pretty vicious (claws and all), this crustacean is all the more dangerous with that knife. As scary as the whole thing must be to see in real life (I hate crabs), there's something infinitely satisfying about watching the cute animal ward off its enemies by threatening them with a knife. It's not something I like to see my fellow humans do, but it works well here.
And in terms of the whole thing being a hoax, well, I don't believe it. It seems pretty likely that a crab is able to hold a knife in its claws, and, from what we've seen so far, it appears that the rats are still dominating the world of performance art.