Smallville :

Clark joins the football team at school and immediately gets promoted to starting quarterback after the former quarterback fights with Jason, the team's new assistant coach.

Curious about the behavior change in his teammate, Clark and Lois investigate and discover that the cheerleaders are poisoning the team's water with Kryptonite, turning the players into perfect boyfriends. It also causes Chloe to become devoted to Clark, and sends a jealous Jason after Clark.