The Almighty Tallest send Zim off to get him out of the way while they prepare for Operation Impending Doom 2.  Dib is the only human to recognize Zim for the alien that he is. 

Of Note:  A slew of memorable quotes, the infamous Doom Song, GIR's squirrel imitation, and Zim's introduction to the class. 

Ms. Bitters's class takes a career placement test to learn what their future careers will be.  Zim ends up in the wonderful world of fast food, while Dib gets involved with paranormal stuff. 

Of Note:  Zim's concluding that he who controls McMeaties controls the world, poor Count Cocofang, and the galactic equinox causing Zim to go through a hideous molt. 

Dib must pass through many difficult tests to reach his father so that he can get a permission slip signed. 

Of Note:  The Cyber Arachnid battle and Gaz's reaction to pizza. 

When Zim crashes his ship, he must return home to get a tow vehicle.  By the time he gets back to the crash site, a clan of UFO crazies have claimed the ship for their own. 

Of Note: The evil death bee, the guy that wants Zim to bless his feet, the "government agent," and "The pig accepts me!" 

Zim discovers that water and Irkens don't mix. 

Of Note:  The giant water balloon!  Go Zim! Go! 

Zim must get the Parent Decoys ready for Parent Teacher Night at Skool or else! 

Of Note: Baby Zim! Gir discovers make-up! "That was my squeezing arm! They took my squeezing arm! Why, my squeezing arm!? WHY!!!" Oh, and can't forget the Parent Decoys taking Zim home!

Zim upgrades Gir's guidance systems and then takes Gir out for a field test. Alas, Gir leaves the "guidey chippy thingy" at home.

Of Note: Zim's compass likes Gir! Zim can't stand the bus! Gir keeps replacing important parts with food. o_O The dancing Mexican! Oh, yes, and keep your eyes on the signs in the background!

After watching a War of the Worlds type movie, Zim does some research and discovers that dangerous little organisms known as "germs" do, in fact, exist. The horror! The horror!

Of Note: The Tallest make a brief appearance! Yay! Zim's little cleaning outfit. Two words... Space Meat!

Zim, when sent to the nurse because he has head pigeons, decides that he needs organs to pass for human.

Of Note: Gaz has a squeedily spooch. Dib uses the old "pencil lodged in his brain" excuse to go find Zim. Zim listing off his organs. "TOOOOORQUE SMAAAAAACKYYYYY!!!!" Dib makes the tabloids!

Zim decides he needs a best friend in order to seem more human. Keef passes the grueling tests Zim decides. Keef is quite the obsessive little bestest friend.

Of Note: Zim's friendship tests. Gir's costume sequence. Zim's present for Keef. Killer squirrel!

Dib manages to photograph Zim out of his disguise. To destroy the pictures, Zim shrinks himself and gets into Dib's body. While he's there, he decides to make Dib's brain "not smart no more."

Of Note: "Computer! Take me to the weasels!" Gir with his slushy. "Arms... Like... Noodles..." The view of Dib's brain and Zim's energy blast! Pwetty! Dib's "finishing move!"