Extra-galactic alien (Men in Black)

thumb|right|340px This extremely large alien only appears in the final scene of Men in Black, when the camera zooms out to reveal that the whole Milky Way Galaxy is contained within a marble, the same being true for several other galaxies as well. The alien, which has a greenish gelatinous appearance and four digits on each hand, is seen playing with some of the marbles before packing them on a bag.

This is by far the largest alien in Alien Species Wiki.

Note: Look at the reflection on the picture.