Casey was a member of SG-2 and who was involved in the first mission to Chulak.
Biography
1997
During the battle at the Stargate which pitted SG-1 and SG-2 against Apophis's Jaffa warriors, Casey was wounded but Colonel Jack O'Neill and Major Charles Kawalsky managed to carry him back through the Gate, sending Casey through to the Embarkation room.
In that split second, an immature Goa'uld that had been in the body of a Jaffa Warrior who had been strangled to death by one of the refugees emerged and instantly slid into Kawalsky's body via his right ear before wrapping itself around Kawalsky's spine, resulting in Kawalsky becoming unknowingly infected with a Goa'uld. (SG1: "Children of the Gods")