Smallville: Season 2, Episode 4

2 - 4: Red

The school unknowingly uses red kryptonite in the class rings and its effect on Clark stuns everyone as he turns into a rebellious teenager who decides to use his powers for evil instead of good. Lana finds herself drawn to the "new" Clark who declares his love for her. Meanwhile Lex is at odds with his father about taking over his buisness.