

In The Fever Code, Doctor Paige says that Grievers have a mutated version of the Flare that can be healed with the Grief Serum. They are assumed to "charge" in oblong cell-like cages seen in WICKED headquarters and at the end of The Scorch Trials. It is unknown if the Grievers intended to go into the Griever Hole. Grievers appear to be easily tricked, as seen when Thomas and Minho tricked the Grievers into going over the Cliff. Grievers have stung four major characters in The Maze Runner: Alby, Ben, Gally, and Thomas. The machinery inside of them often causes the reflectance of light, as described by Thomas. Grievers make whirring and clicking sounds when they move. Stung Gladers who take the Grief Serum usually regain some of their memories during the painful " Changing." If a Glader does not take the serum, they die. A Griever can "sting" Gladers, or prick them, which causes extreme pain for up to days or weeks.

It is described as being a bulbous, dark creature, with many appendages such as spikes, shears, and rods.
