The crew lands in a specially designed aqua-shuttle but is immediately attacked by a sur-snake and Kirk and Spock become trapped in the monster's grip. McCoy says, "We're stumped, Jim. The hormone seems to be the major factor in your mutation but we just can't identify it." Kirk asks, "Are you sure the mutation wasn't somehow accomplished naturally?" McCoy replies, "It's infused into your bodies at key structural points. It had to be done by injection." Kirk demands, "But can't you duplicate it Bones? Your medical computers have information of every procedure in the Federation's hospitals." McCoy says, "It's highly sophisticated and completely unknown to us." Spock inserts, "That implies there are intelligent lifeforms on Argo." McCoy replies, "The sensors don't indicate any life forms dow