Nightmare

The Nightmare is a hostile Typhon encountered on Talos-1 during Prey (2017).

Overview
The Nightmare is the biggest, strongest and most dangerous of all the Typhon. As Morgan unlocks more powers through neuromods, this action will attract Nightmare attention and the creature will try to hunt him down. It will start its hunt after Morgan goes to deep storage.*

* It can start hunting earlier.

Design
Nightmares look like a bulkier version of a Phantom. They posses six white spots that can merge into one, which serve as eyes and seem to float around instead of walking. Nightmare can also shapeshift to better suit doorways.

Strategy
Essentially, your guess is as good as ours.
 * Run away.
 * Gloo it. It can work for less than 10 seconds. Not recommended unless you want to scan it.
 * Unleash all Dakka.
 * Pray to whatever God you worship.
 * If lucky it will spawn in as you are getting on or off the elevator. At that point you are safe from its attacks and can wait out the hunt in the elevator. Then go to a different area for a brief time and head back and it will be gone.

Trivia

 * Nightmare is reminiscent of the Nemesis monster from Resident Evil 3.