Appearance and effects
The Invisible Cretinizer causes stupidity in its victims. As the name suggests, it is invisible. That said, it is not at all known what it would look like if visible. It seems to be small, as Calvin is seen holding it with only his thumb and index finger. It is probably in the shape of a gun of some sort, as Calvin says that "one shot will render the victim a babbling simp, a dolt, an utter moron". Unbeknownst to the class, he then fired it at Ronald, one of his classmates, who immediately heckled him by shouting, "Oh, sure, Calvin. Give us a break!" Calvin then explained that Ronald had just proven that it is rather effective, even at long range. The Invisible Cretinizer was never featured again.