The phrase "alien scum" is a derogatory term used to insult or belittle someone who is not from the same country or culture as you. It implies that they are lesser or unworthy in some way.
Sentences with «alien scum»
You've also died like a trillion times on various alien planets, and your body (if it wasn't smashed into paste by one of your own drop pods) was probably defaced by alien scum. (co-optimus.com)
Pre-purchase today so you can start blasting alien scum with your buddies the moment the game drops at midnight on August 19th. (nintendowire.com)
Call in airstrikes, commandeer tanks, operate giant robots and more to obliterate alien scum. (xseedgames.com)