Pun story....
It's a regular SF story with a pun at the very end. Frequently a very bad pun! The worse, the better, IMO.
My pun story (written almost 30 years ago) had these elements: a prankster named Tuckie, aliens called Blues whose language sounds like cow moos, and an unfortunate protag named Ken. The last line: "There's a Blue moo'in over Ken, Tuckie!"
When you're through groaning, I would almost bet you could find some pun stories on the WWW, much better than my youthful mis-try.