Vanishing Act is the second segment of the 51st episode The Adventures of Jimmy Neutron: Boy Genius.
To impress Betty Quinlan, Jimmy puts on a magic show. Unfortunately, green-eyed monster Cindy sabotages the act and causes her, Betty, Carl and Sheen to get sucked into a strange dimension. Jimmy goes into the dimension and finds them and the Great Spamdini, who helps them find a way home.
This episode displays a unique scientific analysis. As Jimmy enters the dimension, he remarks, "Okay, I'm in some sort of a parallel dimension, so that door isn't real, that eyeball isn't real, and I hope that [toilet] isn't real." implying that no objects are real in a parallel dimension.
While in the green wireframe room, Jimmy remarks, "If I knew that we wouldn't disintegrate at any given moment... I could have some fun here", implying that when in a parallel dimension, matter that takes any form can disappear at any time. Evidence of this in the episode can be seen in the background of the portal hallway. There are constantly portals appearing and disappearing. From another viewpoint, the dimension Jimmy is in contains two intersecting dimensions. Meaning, the force of the magic box must have been built with an extradimensional power that has the ability to warp electrons. Jimmy does describe this to Mr. Spamdini, only to be ruined by the annoying and loud Sheen. Furthermore, the key to finding the exit portal is to locate where the dimensions intersect. Intersecting dimensions, as described by Jimmy, always spit out new matter, which was the tuna sandwich in this case.
- Betty knows about Cindy's crush on Jimmy and says she can have him. That does not stop Jimmy from liking Betty, however, as shown in "The League of Villains".
- The elements in the dimension could be a reference of Super Mario 64 and its DS remake.
- Cindy and Betty would've finally become friends in an unproduced episode titled "Three's a Crowd".