The Red Button
From Mario Fan Games Galaxy Wiki
The Red Button is an imaginary device which Retriever II occasionally "threatens" to use. It has one purpose: destroy MFGG when pressed. As a result, many forum members and RII himself tend to joke about it, and drawings of RII using the button (and of the aftermath) are posted every once in a while.
Even if the Red Button did exist, it seems unlikely that RII would actually use it; in fact, he spent a good deal of effort restoring MFGG from The Great Mistake.
