The Ancient Chest is a structure exclusive to Don't Starve Together, naturally spawning in the Ruins next to an Ancient Pseudoscience Station. It works similar to a Chest, but has 6 slots instead of 9, and cannot be destroyed. Its use is to input items to receive Replica Relic Blueprints, or solve the Metheus Puzzles.
When inserting items, the chest will rumble about for 5 seconds, then will open and either spit out the items that had been inserted if the order was incorrect, or consume the items and spit out the Blueprint if it was correct. If the Metheus Puzzles were solved, the chest will consume the items and not open. A notice on the top of one's screen will state: Metheus has taken heed.