This What if happens during the Battle of Gods movie. 

The 7 Dragon Balls were gathered in order to find what in the world could Super Saiyan God really be, as a God of Destruction was looking for it, but none of the Earth warriors knew a thing.

Shenron spoke to them all that there was a Super Saiyan God a long time ago, but he's long gone... However, recently, there was a new one made... The Saiyan went by the name... Shallot. 

Confused, Daiko asked about that name... He didn't really knew of any Saiyans going by that name in back in the day. Shenron responded that far away, there is a tournament going on... Tournament of Time. Warriors from all of time were taken in to battle it out. 

As hurt as they were, they needed to bring this warrior from that tournament over here, even if just for a little bit, in order to satisfy Beerus's seek for the Saiyan God. So, the wish was made to bring Shallot on Earth for 24 hours, which should be enough to explain to him what's going on, get him to fight Beerus and rest up before heading back to his time.

With the wish being made, Shenron's eyes flashed... And a warrior with dark, spiky hair and a blue, dark ancienct Saiyan armour appeared in the middle of the Dragon Balls...