Rogue Galaxy Quarry: The Labyrinth Terror
The closest save point to teleport to in order to reach The Labyrinth Terror is the Labyrinth - Maze of Chaos location on Rosa. Once you teleport to the Maze of Chaos head into the room with glyphs all over the walls. You'll find the ring to summon the boss on the southern end of the room (where I am in the screenshot).
The boss fight is a pretty easy one, he has the same mechanics as a mimic which you've fought plenty of times by this point in the game.
In order to summon this boss you'll need a Nebuladon Egg. As long as you aren't trying to do the Revelation Flow on every single character you should have a spare one. If you are missing the item required to summon this boss grind some battles and cross your fingers or go treasure chest hunting on a planet you've 100% the map on. In Rogue Galaxy once you pass a certain chapter the loot table of items that can drop for you ingame is updated.
What I mean is, every item has a chance of dropping off every creature after you've passed that chapter that allows that item to drop. At least this is how it works in my experience. Therefore, if you're missing any items to summon any of the quarry bosses all you need to do is grind a little until you get that item to drop for you. Good luck!