Charlie

The Grue (also called Night Monster) is an monster that never reveals itself. The creature only appears at night and only attacks the player when they're in total darkness.

The player character issues a warning if they stay in darkness for too long, indicating that they must find a light source immediately. This is followed by a sound that resembles a deep inhalation and, ultimately, a "swipe" at the player. One attack from the Grue does 66.7 damage. After the swipe, the cycle will repeat. The attacks will continue until a light source is found or the character is dead.

Acceptable Light sources include: Torches (while held), Fire (camp or environmental), an equipped Miner Hat, Pumpkin Lanterns and Willow's Flame. Fireflies are also acceptable, but disappear as soon as you get into their vicinity. Standing next to a Crock Pot that is cooking can count as an acceptable light source.

The player cannot see the Grue at any given time because there is no visual of it added in the game.

Trivia

 * Grue is a reference to to the iconic monster from the game Zork
 * In the game code, Grue is referred to as "Charlie".