Dib Membrane

He is an eccentric young boy who is obsessed with the paranormal. He's the older brother of Gaz Membrane and son of Professor Membrane. Self-proclaimed "defender of Earth", he attends skool with Zim and is determined to stop him from conquering Earth or expose him as an alien, though almost nobody believes him. He is highly unpopular at school and at home for his said obsession with the paranormal, and is often dismissed as "crazy" or "insane". Despite being a foil to Zim, he's frequently shown acting in selfish, self-centered ways. Dib is separated from the rest of his peers by his exceptional intelligence and determination. Also, Dib continues to seek out the paranormal despite the considerable ridicule he receives from both peers and family.

He considers himself to be the sole defender of Earth against Zim's plans of conquest, and rightly so; he's in fact the only one who knows (or cares) that Zim is an Irken Invader bent on world destruction.

When Zim first landed on Earth, Dib was initially shown to be more antagonistic, obsessed, and desperate, making it his sole goal in life to expose Zim as an alien by any means necessary.

However, he eventually realized that any efforts to reveal Zim would be wasted on his oblivious and mean spirited peers, and Dib eventually lost his obsessive, desperate edge, becoming a more humorous, depressive and more sympathetic character overall. His hatred of Zim eventually becomes real as the Irken takes every opportunity to make his existence even more miserable than it already it is even when unprovoked, making Dib's efforts to beat Zim all the more personal.

Dib shares his father's scientific and technological prowess, with skills that far exceed the average human being. He has been known to created advanced technology entirely from scratch (for example, an advanced water balloon-launching apparatus).

These skills aren't limited to just Earth-based technology, either. Dib has on multiple occasions proven a keen understanding of Irken technology as well, whether it be hacking into Zim's base, reverse-engineering a rogue Invader's crashed vessel, or remotely flying the Irken flagship itself. Dib Membrane is an extremely intelligent boy. He shares his father's scientific and technological prowess and is even shown to be slightly more intelligent than him, being the only one to see through Zim's (terrible) disguise. He has the ability to build advanced technology just from scratch. he is really a fast runner

they are in the cafeteria and dib is stalking his enemy zim to see if he's hiding something