just after building a little dirt jump in by back yard i go up the street to get some speed I HEAR THIS LOUD SNAP thinking my chain just fell off But i look down and SEE MY REAR DERAILER INSIDE MY WHEEL (WTF) and this is were i should stop telling my story
the pics explain a lot

And now i am just wondering how much a rear derailer is going to cost

whats missing here

it looks like the drop out can be replaced

NO Riding for a while (this Sucks)