Inspiration for the Weighted Companion Cube came from Project Lead Kim Swift, with additional input from Erik Wolpaw, after reading some "declassified government interrogation thing" whereby "isolation leads subjects to begin to attach to inanimate objects". Swift commented, "We had a long level called Box Marathon; we wanted players to bring this box with them from the beginning to the end. But people would forget about the box, so we added dialogue, applied the heart to the cube, and continued to up the ante until people became attached to the box. Later on, we added the incineration idea. The artistic expression grew from the gameplay."
Wolpaw further noted that incinerating the Weighted Companion Cube became an introduction to the idea of incineration, which the player would need to learn in order to complete the final boss fight, and by training the player to do it with the Weighted Companion Cube, found the narrative "way stronger" with its "death".
