The Thinker's Box is one of the many monster drops that can be acquired in the Frontier. It can be acquired through multiple means that include but are not limited to:
- A possible gift from the Otherworld Present.
- A possible reward while exchanging fireflies with Stick during the Firefly Quest.
- A possible reward from a regular Treasure Chest.
- A possible reward from a Grand Treasure Chest.
- Killing a Forest Guardian.
- Killing a Gumbo.
- Killing an Otherworldly Dollhunter.
- Killing an Otherworldly Knight.
- Killing the Parasite.
- Killing a Ratdog.
- Killing a Two-Eyed Monstrosity.
- Killing a Whapper.
- Purchasing it from Linkman the Junkman at a price of 175,000 gold.
In appearance, the Thinker's Box appears to be a cube that strikes a 'danger signal' to the players' conscious minds. Weird, unnatural-looking figures can be seen at the very top of the cube.
Like most monster drops, it is typically sold to selling vendors in sanctuaries. It does not have a relevant purpose in-game, with the exception being turned in in exchange for a reward while doing Slayer's Tasks.
- It may be a reference to the Pandora's Box.