Neefed It Up

To mess up or cause a failure, this term was popularised by the YouTube Channel Oliver Aged 24 (HowToDrawReallyGood ) where Neef (a previous student of his) would show some of his pieces of work that he created using the tutorial, they are always terrible and referred to as being 'Neefed up'.

"You have Neefed it up"
"You've really Neefed this up!"