Rob Petrie was an alias used by Fox Mulder. He assumed the name while investigating The Falls at Arcadia with Dana Scully, who meanwhile took the name Laura Petrie. Mulder specified the pronunciation of his and Scully's assumed surname as "petri, like the dish." (TXF: "Arcadia")

This name was actually taken from The Dick Van Dyke Show, starring Dick Van Dyke as Rob Petrie (pronounced Pet-Tree).