The Ancient Crystal is one of the three Power Crystals. It controls history. Its shape controls what has happened in the past. For example, if the crystal is in its normal form everything will be normal. If the crystal is shaped like a triangle, then everything will look like there has been a war.
Montgomery stole this crystal in The Floorsland 2. He tried to shape it like a square (which would mean The Floorsland never existed), but it was too hard. Tim was able to retrieve the crystal by using a teleporter. That turned on Montgomery's alarm systems and he jumped from the platform he was on, but he didn't find any intruder because Tim had already escaped with the crystal.
- Only the king knows where this crystal is located. It is unknown how Montgomery found out where it is.