This was my own theory, just something odd. I know that in Invader Zim, humans and aliens alike have weird fingers. Most humans have four, but the only human that has three, like an Irken, is Keef. Keef. Remember? Zim's 'bestest friend'? Of course you do! But why is he always so close to Zim? This theory states that Keef is also an Irken Invader, only, when Zim almost destroyed their home planet with a giant laser robot (See The Nightmare Begins), he fled to Earth and developed even more of a hatred for Zim, alongside Meef, his younger brother, whom he also fled with. He is trying to make him flee, or at least give up. Here are some other facts to prove this theory
- Why did Keef come into Zim's house?: He wanted to find a way to sabotage him!
- Why was he cooking?: He knows there are secret ways to get into the lab, and he is trying to find a way to activate it.
- Shock and Absorbency Testing: We see that in Bestest Friend, Zim tests Keef for shocks and absorbency. Since we see that Zim is harmed by electricity and water, he wants a friend who is at least a bit resistant against it, and some Irkans are, just like Keef!
- Since he has been here since Operation Impending Doom 1, he knows how to act like a human more.
- But also, since he has been there a long time, he is unfamiliar with, or forgot about, Zim's eye replacing trap.