Spiderdemon/Doom (2016)

"The first Project Lazarus Tethering Operation (MTC 2146/351) retrieved a small compendium from the Umbral Plains in the crypt of a destroyed tower of unknown construction (artifact reference PL E2M8). This "vade mechum" was mostly illegible, but it did contain one of the rare references to the Aranea Imperatix - a mystical demon that is still largely unknown.

"When the gate is opened, in the fourth age, when we have risen and the masters have shown us the path, she will be come. A great blessing will be given to the key holder, for they will become one with the master, and in that holy union the power of the dark priest will be unleashed upon the heretics of the Penumbral Plain. The Aranea Imperatix. Carried in the mind of all who follow, fed from the blood of those who fell, made with bone of rock, iron, steel and sinew. A mighty god to rule over all other gods. One become two become legion.""

- Spider Mastermind Codex entry, UAC report file FVS1EC3F

The Spider Mastermind is the final boss in Doom (2016) and is the demonic transformation of Olivia Pierce.

The Spider Mastermind has a large health pool and has a number of attacks which can cause serious damage to the player, such attacks include a melee attack with its legs, several laser weapons, an electrical area attack and some sort of telepathic attack used when its health is nearly depleted.

The Spider Mastermind's exposed brain is a weakpoint, especially when hit with the Gauss Cannon. When weakened, it will crawl on its remaining legs to support itself and will turn upside down on itself to shoot lasers.

Upon defeating the Mastermind, the player will initiate a unique glory kill which involves opening and inserting the barrel of the BFG into the Mastermind's mouth and firing the weapon.

Trivia

 * The codex entry of the Spider Mastermind makes reference to E2M8: Tower of Babel, a tower that functions as a pathway to Hell that was constructed on Deimos. Whether or not the tower constructed on Deimos and the tower where the vade mechum was found are one and the same is unknown.