A Griever is a creature that lives in the Maze and comes out after dark and it's purpose to kill the Gladers, with the exception of Gally. It is described as being a bulbous, dark creature, with many appendages such as spikes, shears and rods. The Griever can "sting" Gladers, or prick them, which causes them extreme pain for up to days to weeks and brings some of their memories back, a process known as "The Changing,"but only if taken to the Grief Serum. If it is not taken with the serum, it causes death. Grievers makes a whirring and clicking sound when it moves. The machinery inside of them often causes the reflectance of light, as described by Thomas. The Grievers have stung four characters in the novel; Gally, Alby, Ben, and Thomas, along with a few other characters. Also, the griever is described as a slug/cow-like creature who pricks you and usually is connected to a beetle blade. They have sharp metallic objects poking out of them they and are like green, furry slugs the size of a cow, but yet they're dumb as dirt, easily tricked when Thomas and Minho trick them into going over the Cliff, yet it is questioned if they were really intending to do it on purpose. They are assumed to "charge" in oblong cell-like cages seen in WICKED headquarters and at the end of the Scorch Trials.