4x20 - Ageless Evan, the freak of the week, ages rapidly and is about to self-destruct in a huge explosion. His last words are "I wish you were my father, Clark." To be more specific, Clark and Lana find a baby boy in a field and adopt him. Unfortunately, the baby, named "Evan," starts aging rapidly and, despite everyone's best efforts, dies. The worse part was the scene where Evan's biological father didn't want anything to do with him.