Describe how you are invisible, and how he is impossible to you. There's plenty of imagery to be gained from just describing the two key points of your poem.
"I like refried beans. That's why I want to try fried beans, because maybe they're just as good, and we're just wasting time." - Mitch Hedberg (1968-2005)
"Football is about if you want to run and fight for each other, if you really want to play that killer ball." - Robin van Persie, Arsenal FC