This one-liner may be used during an alien invasion, especially when you're a badass who is out to kill the beasts from outer space.
It is also possible to get the phrase as a dirty joke, according to the youtube celebrity Jesse Cox from the youtube channel "OMFGcata", who first came up with this sentence during his playthrough of the game "Crysis 2".
You kill an alien with your mere hands. You mention that you are choking a squidhead. You throw his corpse away.