"
And when I get back,
From outer space,
I'm gonna punch him in his face
This can be taken both ways literal, or metaphorically.
Literal meaning: When she comes back from where she lives, she will punch him in his face for what he made her feel.
Metaphorically meaning: She will come back to him and punch him in the face, meaning to give him a wake up call telling that she's in lobe because of him.