In 2269, Clayton piloted the aqua-shuttle from the Enterprise to the surface of the planet Argo. During the mission he was ordered by Kirk to open the shuttles hatch so Dr. McCoy and Spock could retrieve seawater and algae-specimens.
Just as he was preparing to open the hatch, the shuttle was attacked by a sur-snake and Kirk ordered Clayton to stun the creature with the shuttle's phasers. Kirk then ordered Clayton to submerge the shuttle so that they could study the creature before the stun effects wore off.
While studying the sur-snake, it suddenly awoke and, again, attacked and eventually destroyed the shuttle. During the encounter Clayton and McCoy were thrown clear of the wreckage, and survived with no apparent injuries.
After returning the planet again to search for the inhabitants of the planet, he would again pilot the scouter-gig, and later take command of it when Scotty was forced to locate Kirk and Spock of an impending siesmic disturbance. (TAS: "The Ambergris Element")