Final Fantasy X is a video game in the well known JRPG series from Square Enix.
Run around in the Omega Ruins and you will encounter treasure chests in battle. Steal from them and about 75% of the time they may become Mimics. If you defeat them, you will get 50,000 gil. In all the other encounters there, you can get some valuable four slot equipment to sell or customize.
When you see a chest in battle and attempt to Steal, it is sometimes a Mimic. Use Mug instead of Steal and you can still get the treasure if it is an actual chest, or kill the Mimic if it is not.
Remiem Temple: Cloudy Mirror
Fly in the airship (obtained immediately after you finish the Zanarkand Ruins) to the Calm lands. Go to the Chocobo rider standing still directly out of the Al Bhed location where the Airship dropped you off. Take the Chocobo to the southern entrance and go east to where you see a Chocobo feather. Press X over it and the Chocobo will jump down. Go into the entrance that you see.
You will see a huge temple and bridge leading to it. Go across the bridge and move to the left side, not through the door. Examine the sphere you see and then go to the opposite side. Press X near the Chocobo and race it. Win this race and get the Cloudy Mirror (which is the Celestial Mirror's first form).
Remiem Temple: Entering
Ask the Chocobo girl to ride a Chocobo. Ride it all the way down were you usually start out races with her. Go all the way to the end to find what resembles a yellow Chocobo feather. Press X on the feather and the Chocobo will back up, jump off the ledge, and land on a new section of land. Go to the exit of that section of land. The next screen will show the Remeim Temple.