Bill Cipher sighted in arcade, on the -12 dollar bill, on Dipper's shield, on carpet, on window, and in "The Amazing World of Gumball"

The pictures you see below have some Bill-related secrets in them.
You may have seen them already, and I'm sorry if you have, but
        if you haven't, try to see if you can find Bill Cipher.

These pictures all show Bill Cipher in the back round. It seems like he is the most important character in the whole show. He's gonna do something about a million times worse than anything he has ever done before. I know it. Some people think he will cause an apocalypse, and that could be correct, but that's another story.