For the Love of God, Stay Awake!

"He was left with only a few simple choices: to cry out or keep his silence, to bleed to death or take his knife and end it quickly, to stay awake or fall asleep. At the moment, sleep seemed a tempting prospect. He was tired and bone-weary, fatigue pulling at his sluggish mind like an insistent friend, but he would not yield to it. He knew if he fell asleep now he would likely never awaken. Just as he knew that all these so-called choices were simply illusions. In the end, there was only one stark choice left to him now to live or to die and he refused to die."

- Mitchel Scanlon

Humans need sleep. It is part of how are body preforms maintenance. When we are tired, we feel the temptation to sleep. However, sometimes falling asleep can be a very bad thing. This is a situation that usually tests will power. If the person passes this test, his mind and body are only denied vital maintenance, if the person fails something worse happens. Simply put, this trope is if someone falls asleep, something worse than the standard effects of loosing a single nights sleep occurs. Sometimes sleeping is punishable by death (e.g. sleeping while on watch in roman legions). Sometimes someone is in less then hospitable conditions, and if that person falls asleep, he won’t wake up. Other times its something different, sometimes falling asleep even has consequences worse than mere death.

This is a very common thing in fiction when a character has a concussion, and a great opportunity for other characters to plead for the injured to "stay with me!"

Please note that in some cases this might be a case of Artistic License Medicine. If this trope is done for medical (or maybe even environmental) reasons in the show that does '''not mean you should consider it sound medical advise. Often getting sleep helps getting better (as said above, sleep tends to provide the body and mind vital maintenance).'''

This is a supertrope of Never Sleep Again, a Horror Trope that describes monstrous supernatural reasons for forcing oneself awake—physical nightmares, dream invaders, and the like. More mundane examples are listed below.

Real Life

 * In the Roman Legions those caught sleeping on watch were to be killed, at least during time of war. For at least part of the existence, the execution preformed by clubbing, from the transgressor’s comrades.

Anime & Manga
In Daily Life with Monster Girl Centorea tells Miia (who is cold blooded) that she will die if she falls asleep. This is because of the cold temperature, that Miia caused to make the new household member uncomfortable.

Literature

 * Fifteen Hours Larn gets injured in no-man’s land and knows that if he falls asleep he almost certainly will never wake up. It also provides the page quote

Fan Fiction
In the My Little Pony Friendship Is Magic (Animation) fanfic, Solitary Locust, Twilight suffers injuries that put her in this category.

Western Animation

 * This happens to Yumi in an episode of Code Lyoko due to being out in a blizzard caused by XANA.

Anime and Manga

 * In Naruto when Gaara sleeps, the demon sealed inside him eats away at is soul. Unsurprisingly gaara developed insomnia. Because of how long he was exposed to this trope, and sleep’s importance in mental maintenance, the lack of sleep was taxing on his sanity.

Music

 * The Creature Feature song "Look to the Skies" (which is probably based on Invasion of the Body Snatchers) provides a quote on the quote page. If you fall asleep (at least at night) aliens do something bad to you.