The Purple Spaceman is possible human who was traveling around Space picking up people who are stranded. He soon came into contact with the Blue and Orange Spacemen, where he offered them a ride in exchange for some space love. Blue gave in and was prepared to give him space love, but Purple got overenthusiastic and started getting undressed while he was still in a vacuum environment. As a result, Purple exploded and sent his spaceship into space, leaving behind only a helmet and a crate.
Purple's memory lives on with his helmet that Blue and Orange have, a video of him exploding on Orange's Spacebook page, and his steroids-abusing brother.