GPE - GRV for Ampharos, GPE - FtMGS* for Natu. Warnings all around.
Not DEC, since the draw was legal, just to get that out of the way. No other GPEs apply, so GRV. (*) Depending on how long the turn post-GRV took, I may not give FtMGS.. If Ampharos was playing fast (“Force Away your guy and swing for 4. Pass.”) it's close enough to “immediately” to work for me, but if they were playing at a “normal” pace, it's definitely too long.
As for the remedy, assuming that Natu has not yet drawn for turn, we have a simple and easy rewind. Undo the untap and combat, have Ampharos properly resolve Force Away, and have them play on. Edit: Oh yeah, this is
actually a partial fix. No rewind, have them discard a card. My bad.
Edited Suhas Arehalli (Sept. 25, 2014 12:09:45 AM)