Q: What do you call a fake noodle?
A: An Impasta!

Explanation: Noodles, such as spaghetti noodles, can be called pasta.
An imposter is a person who pretends to be someone else.

So, a fake noodle is an “impasta” which sounds like a combination of imposter and pasta… and that is what makes this joke funny.

Did you see the movie The Imposter?  Here is the trailer: