The octopus. Without a doubt, it's the octopus. All hail the new octopi overlords!
No joke... The octopus would be my guess as well. They are crazy intelligent, many people don't realize this. They can solve complex problems and manipulate their environment.
My local fish store (aquarium) carries very exotic fish. A few years back the owner had a octopus in a show tank. He'd put a piece of food in a glass jar with a lid screwed on tight into the tank... that octopus learned how to open the lid a get the food almost immediately.
Then the little fucker decided that he wasn't getting enough food for his liking. The owner of the shop thought that he had an employee stealing some very expensive fish because they were somehow disappearing. So he put in some cameras. He couldn't believe it when he watched the tapes one morning and saw what was happening. The octopus was strong enough to escape from his escape proof tank. This octopus would actually climb out of his tank and climb into the other tanks in the store... sometimes crawling a good distance along the floor and then up a cabinet in order to get to other tanks. Unbelievable. Then he'd eat the fish in their tank be very sneaky about it, and then he would crawl back to his own tank and break back into it so nobody would suspect him. Insane.
The owner got rid of the octopus soon after. Hahahaha
For the record,,, I'm doing my part to stop the octopus take over. I love to eat octopus. Used to eat fresh ones that I caught back in Hawaii all the time... no days I order a shit load of it at my local sushi restaurant. It's one of my absolute favorite foods.
They're watching us... don't fucking trust em.