Ok, so to have a running blog post, I'm counting down the top 10 aliens of science fiction throughout any media. Be aware, there are many SF TV shows I don't watch, Dr. Who coming to mind, so I probably won't represent that aspect fairly. Regardless, blogs by definitions are opinions. Here's what I like.
These are the pixelated beginnings for video game SF. Parents of the late 70's didn't care if their kids were killing aliens at the local arcade. This idea is an extremely basic reason for the rise of so many non-human enemies in video games. Who cares about killing extra terrestrials that want to destroy our precious earth?
What strikes me about the Space Invaders is that they were the first instance of a zerg rush, granted humans weren't controlling them. The one-man laser cannon could easily kill a single alien with its rectangular beam but the shear number of little guys was the real problem. In addition, we have an instance of aliens getting progressively dangerous as time passes, a timeless attribute found among the galaxy's residents.