Doctor Graydon was a scientist who went on a mission with a contingent of Atlantis personnel to the Mobile drilling platform in the ocean on Lantea. He was killed by the Wraith Queen that had found a way into the platform. (SGA: "Submersion")
- McKay mistakenly calls Dr. Graydon "Grayson," and likens him to Bruce Wayne's Ward, Dick Grayson, during the search for the drilling platform.
- Dr. Graydon claims that one day he would call McKay "Dr. McCoy", the fictional doctor from the original Star Trek series, after McKay repeatedly forgot his name.
- It is implied by McKay and Dr. Dickenson that Graydon was hired by mistake, instead of an actual Dr. Grayson.