Last year, when a Japanese supply craft was sent to the International Space Station, there was a stowaway! The below picture is an unknown piece of equipment, however, there's a little laser etching someone has done of Wheatley from the video game Portal 2.
Valve, the developers of the Portal franchise said at the time "Thanks to an anonymous tech at NASA, Wheatley is actually going to actual space." At the end of Portal 2, once Wheatley has embodied GLaDOS and become power mad, Chell and Potato GLaDOS overthrow him and put a portal onto the moon to send him floating through space. So, it seems someone must have a good sense of humour to actually do this to a piece of equipment, although the person who did it remained anonymous. Valve again said "NASA in no way officially endorses secretly laser-engraving characters from Portal onto their spacecraft." As a lover of video games and science, I like spotting connections between the two. Like the 'Tesla Claw' in Ratchet and Clank, or 'Casimir mechanism' in Call of Duty, or Guile's 'Sonic Boom' from Street Fighter.. and many more.