A way to signify someone screwing up, or failing miserably.
Made
famous by the 11 year old Youtube
trainwreck "Jessi Slaughter" aka "kerligirl13" and her
Father.
Your
daughter is posting nudes on the internet.... ya dun goofed.
All ya
haters aint got nothin on me, ya dun goofed, I'
ma make a brain slushie.