Deep Sleep

"As far as he could remember, Sam slept through the night in deep content, if logs are contented."

- J. R. R. Tolkien, The Fellowship of the Ring

Sleep. Deep, profound, unwakeable sleep. Not imposed on the sleeper but springing from his own need for sleep.

Often a consequence of Post Dramatic Stress Disorder. Exhaustion, illness, and recuperation can also produce it. And some people naturally sleep deeply. Usually the deep sleeper does not dream; indeed, the victim of Recurring Dreams may attempt to exhaust himself to invoke this trope. Any Instant Waking Skills are usually nullified, and it takes a lot to wake someone in this sleep. (Which gives people leeway to act about him, whether to move him, or to play pranks, or whatever. Often plans are made and actions undertaken without him, because he needs to sleep.)

A Heroic BSOD is likely to cause this as well; compare Angst Coma. Although it is often termed "sleeping like the dead," if you actually think he may be dead, the trope is Faux Death. If the length is done hyperbolicly, see Asleep for Days; Deep Sleep does not actually need to be prolonged, but can be.

Truth in Television. Merges insensibly with unconsciousness, since the hallmark of true unconsciousness is inability to be woken.

Literature

 * Sam in The Lord of the Rings. Not only does he sleep like a log in Tom Bombadil's, in Lothlórien, when the other hobbits are talking about sleeping in the tree platforms, he annouces that once he gets to sleep, he won't wake up even if he falls out. (And the less that is said, the sooner he will nod off.)
 * Eowyn is in this while Aragorn is healing her, unlike Merry.
 * In Chris Robeson's Blood Ravens novel Dawn of War II, when the two boy are exhausted the Blood Ravens carry them, and they do not wake even when the Blood Raven shoots off his gun next to them.
 * In KW Jeter's Morlock Night, the narrator, when he wakes, finds that Dr. Ambrose and Miss Tafe have waited for him. He apologizes, but he had never had such a deep sleep.
 * In Jane Yolen and Midori Snyder's Except The Queen, Robin sleeps profoundly in Serana's house.
 * In Angie Sage's Syren, Septimus Heap sleeps so deeply that he forgets Spyt Fire and all but panicks when he remembers.
 * In Gene Stratton Porter's Michael O'Halloran, Mickey is terrified by how deeply Peaches sleeps the night after he brings her home.
 * Elizabeth Kerner's Tales of Kolmar universe has the Kantri go into what's called a "Weh sleep" when they're seriously injured and need to heal, or when they're due to grow, as they grow in stages throughout their lengthy lives. In the latter case they have between a day's and an hour's warning, and then they start to tear away their own armored scales before falling asleep. Then their other scales fall off and soft new ones are exposed. Over a course of months or years they grow and harden while asleep. If they're almost finished, they can be woken by a good friend shouting their truename, but if not... In The Lesser Kindred, when the Kantri, Nikis is at a stage where it's impossible to wake her, and she has to be bodily carried away at great effort.

Live-Action TV

 * Elliot from Scrubs is such a deep sleeper that JD could trip and fall over her, then leave for an hour, run back to bed and trip over more stuff and land next to Elliot just in time for the alarm to wake her up.

Webcomics

 * Impure Blood: Roan is out cold after his escape.
 * Precocious: During break, offering such chances
 * And again.