As part of the ESA's landing of Rosetta’s Philae probe on Comet P67, the photoshop wizards came out in style. I think I saw just about every variation possible about of "alien in corner of picture" possible - Marvin the Martian, Alien, Daleks (and every other Doctor Who character), etc. The one picture that stood out for me was this one: ¹

If you don't know who those two aliens are then you had a shallow childhood and you should spend the weekend on YouTube. Here's a little clip to get you started:

Yip Yip Yip Yip....