First time in the series the name 'Kryptonite' is used. Clark tells Pete the actual name of the meteor rocks being known by this name.
Lex asks Clark if his friend is suffering from a Napoleon or a messiah complex. This is ironic because Lex suffers from something like a Napoleon complex, and Clark suffers from something like a messiah complex.
Items in Lex's room of obsession include drawings from the Kawatche caves, his crashed car and the computer simulation of how the accident happened made by Roger Nixon, meteor rocks, a dead parasite, images of the octagonal disc, a Nicodemus flower, information about Clark and the Kents, and the family tree paper that Clark had doodled Kryptonian symbols on, suggesting that Lex may suspect a connection between all these things.
Once Clark believes Cyrus is from Krypton, the idea of approaching him with kryptonite comes up. This is similar to the comic character Mon-El (Lar Gand), a Daxamite who was believed to be Kryptonian and possibly Kal-El's brother; once Clark came with a piece of kryptonite covered in lead, Lar Gand remembered everything and revealed Daxamites are allergic to lead. He was then sent to the Phantom Zone while Clark tried to find a cure.
Clark uses the following abilities in this episode: super strength, super speed, and heat vision.