Not a favourite episode of mine, as there is no real villain. Tony Todd guest stars as Earl who has an unknown mineral in his skin and causes his body to try and push it out in a jitters like way. His involuntary shaking is extremely strong and because it's kryptonite in his skin, he weaken's Clark and disables his abilities.
He continuously looks for level three at the LuthorCorp plant, but according to everyone, it doesn't exist. The effect of the jitters looks like a visual and special effect at the same time. It's not very exciting to watch and after the third or fourth time happening in the episode it can get quite tedious to watch.
Aside from that, the character of Earl and the plot of the episode is kinda dull. I don't actually like this episode very much. It seems more like a filler episode just to continue showing Clark's ability to be a hero and show off his powers.
No real character development happens, chemistry between the characters is not really shown, and the only real action is at the end of the movie. However, the action that is shown isn't a fight between Earl and Clark, it's actually just an accident that causes Clark to struggle to save Earl and Lex.
Lex is basically the only character to gain development from this episode aside from Clark. He tries to be a hero and save all the high school students from Earl's jitters or whatever he's planning to do to get to level three. Not that it's a bad thing, but this episode doesn't contain many things enough to enjoy it as the previous episodes have. I merely watch this episode for the sole purpose of it being in chronological order to get through the season.