When all your friends turn into douchebags when they were once nice. It's real.
"Don't be a sod."
Billy: Hey dude, wanna go to the movies today?
Todd: No dude I got in with the wrong crowd, now I have sudden onset douchebag syndrome.
An instrumental song by the Japanese hard rock band, Band-Maid.
They should've given Akane a longer solo, but the main focus of Onset is, of course, Her Shreddiness, Kanami.