When you get to the Level 37777 map, activate one of your bonuses instead of fighting the boss at the center of the map. Equip +encounter rings and search all tiles on the map until the bonus literally becomes "?!". Fight on that tile for a chance to encouter an enemy that looks like a door. If you defeat this enemy you will warp to a new area with several enemies that look like crystals. Defeat these tough foes for a chance to earn a gem that boosts one of your stats by +4 or even better +5. There are five crystals to challenge in all, one for each of the main stats: HP, ATK, DEF, AGI and LUC. Good luck!