THE GREEN ARROW INJECTS HIMSELF WITH A SUPER-DRUG TO BECOME INVINCIBLE -- Clark (Tom Welling) discovers the Green Arrow (Justin Hartley) was shot while trying to save a couple from a carjacking, but Oliver denies he was injured. However, when Oliver starts displaying erratic behavior, Clark and Chloe (Allison Mack) investigate and discover he is taking a super-drug that causes his body to heal itself but has severe side effects. Meanwhile, Lana (Kristin Kreuk) makes a shocking discovery that will impact her relationship with Lex (Michael Rosenbaum.) Erica Durance, Allison Mack, John Glover and Annette O'Toole also star. Todd Slavkin & Darren Swimmer wrote the episode directed by James Marshall (#2T7708).