Maybe you've seen the proverbial bunny in a patch of clouds, or a clown's face in a mud splatter on the side of your car? Seeing recognizable objects or patterns in otherwise random or unrelated objects or patterns is called pareidolia.
It's a form of apophenia, which is a more general term for the human tendency to seek patterns in random information. Everyone experiences it from time to time. The ability to experience pareidolia is more developed in some people and less in others.