TK-421
ID number of the stormtrooper sent to guard the Millennium Falcon as it rested in the first Death Star. He was disabled by Han and Luke when they slipped out of the ship. Note that this stormtrooper's designation is noted as TX-421 in the Marvel Comics adaptation of Star Wars: A New Hope. Also note that the Star Wars Trading Game - A New Hope expansion set claims TK-421 was a clone.