wait, what?
So wait a minute, is that some sort of catnip chocolate then? Or is that a REALLY smart cat who was thinking "if I roll around in the chocolate, the humans will like how I smell and shower me with things that I want". The whole point of this thing, it hinges on the punchline which is unclear, ahhhhhhhh! Oh well, it's a short, senseless sort of thing, but it's harmless and not annoying.
By the way, you should keep chocolate away from cats. Not that they'd like it (since all cats from tigers to housecats have a defective gene that prevents them from experiencing the taste of sweetness), but chocolate is actually a vile poison to most mammals; caffeine is a far more powerful alkaloid toxin with greater effect on most creatures than on humans. It's a powerful heart stimulant, it's just a stroke of luck that it isn't effective on us as, say, foxglove. So don't let dogs (or anything else) have chocolate either. Just a little FYI. Unless that thing is a heartless robot with just the brain of a cat. Then you can feed it all the chocolate you want.