I know this was a joke on Facebook, the thing about storming Area 51. But, what catched my eyes is the "them". Is this playing on word? Or, is this grammaticality sound? Or is this a joke because I, as non native speaker, don't get it. Isn't it supposed to be:
Let's see them, the aliens
Let's see the aliens
I hope this question isn't off-topic but I really want to know.