Doctor Who S00 E102 Tonight's the Night

"Space. For all."

Jack Harkness enters the Doctor's TARDIS and discovers a blue-headed alien who claims to be a regenerated Doctor. The alien gives the game away when Jack notices that he's armed, something the real Doctor would never be. The alien identifies himself as Sao Til, a literal arms dealer who trades in limbs. Jack draws his gun and the two enter into a standoff before...