After returning Rayquaza to May and the lake guardians to Dawn, the party can engage in battle with Red in a short boss rush. The following battles must be won without changing your party or refilling your inventory (although the party is fully healed between fights):
Every three turns Red will heal a random active Pokemon for 30,000 HP.
The prize for winning is 1000 Galaxy Coins and Mega Stone. If the party already has Mega Stone, the prize is just 1000 Galaxy Coins.
Note: Prior to the December Hotfix, the prize was only 1000 Galaxy Coins.