Pick your poison

[parepat]

Strange play that happened to one of our guys recently.

Third down and ten at A's 10. A1 drops back to pass under a heavy rush into the end zone, where, under duress and to avoid a sack (as determined by the Referee) he shovels a forward pass to A#80 who was ineligible because he was covered by an end (A#80 was an extra tackle held in to help with pass blocking.) A#80 catches the ball at the A 5 yard line and is tackled at A's 10. What foul (if any) and spot of enforcement.