Imaginary friend. When you want to blame some one just say Shimmy Sham did it or when you need to intimidate someone or project that you have at least one more friend, just refer to Shimmy Sham.
When you want to intimidate someone tell them:
"Stop messing with me or I will get Shimmy Sham on you".
When you had nothing to do over the weekend:
"Shimmy Sham and I were hanging out"
When you want to avoid doing something or going out with somebody:
"Sorry I can't make it, I got plans, me and Shimmy Sham are going to pickup 2 chicks downtown".
When you want people to think you are crazy or have a vivid imagination, end all your sentences with: "Ain't that right, Shimmy Sham?". For example: "Kanye West is a punk! Ain't that right Shimmy Sham"? (Beware: If Shimmy Sham answers you back, seek medical attention).