The Companion Cube is an item used to summon a Companion Cube pet.
- The pet resembles a metal block with a heart in the middle. Just like all pets, the Companion Cube will follow the player indefinitely until they die or the buff is cancelled.
- It possesses the ability to activate pressure plates, and emits strange noises similar to various boss deaths when it touches lava.
- Occasionally, the Companion Cube will stab the player, but only in dark areas, dealing 1 damage to the player. This can kill the player if they are at 1 HP, giving the unique death message, <player name> was stabbed.
- The chance of the Travelling Merchant selling the Companion Cube is 1/10000 making it the rarest item in the game. It is also the most expensive item in the game, costing 5 platinum.
- The Companion Cube is an object that can be interacted with from Portal 1 and Portal 2 Developed by Valve.
- The strange human-like noise it emits when it touches lava, as well as the tooltip and buff tooltip are all direct references to the same item in the Portal games. A possible explanation for the human noises is from the popular internet theory that humans are stuffed inside of the cube.
- It is probably the most or at least one of the most expensive items in Terraria 1.3.1.
- The tooltip "Will never threaten to stab you and, in fact, cannot speak." Is a direct quote from GLaDOS after she gives you the cube in chamber 17.
- Added to the game.