I think there are at least two plausible explanations: 1. They are actually from Earth, hiding somewhere on the bottom of the ocean. Probably Von Neumann probe

I think there are at least two plausible explanations: 1. They are actually from Earth, hiding somewhere on the bottom of the ocean. Probably Von Neumann probes which arrived millions of years ago, and not actually living things. They check our status periodically and send information to their origin system. 2. We are living in a simulation, and they are spectating us in a god mode with a visible side-effect.