earworm
It's at this time when your brain, gets really gives up and think of a song that you hate so much. This mostly happens when your doing something really important yet really boring so you think of one word and your brain will think of a song that you try to get rid since last week.
Teacher: Ok, there are food in the plastic bag. What is inside the plastic bag?

Guy: *hmmm plastic bag*

His brain: DO YOU EVER FEEL LIKE A PLASTIC BAG DRIFTING THROUGH THE WIND WANTING TO START AGAIN!!!

Guy: GODDAMMIT, PLS STOP THE EARWORM!!!!

Teacher:earworm?