Wake Up Fighting

From Roger Ebert's Movie Glossary:

To prove how aware/crazy/focused a movie character is, a friend will wake the sleeping character. The character will instantly, ferociously, leap up from a deep sleep and pull a knife/gun or kung-fu chokehold on his friend, before apologizing for almost killing him.

Basically, a character wakes up violently, drawing any weapons or techniques in the process.

Compare Ring Ring CRUNCH, Instant Waking Skills. For a similar reaction from someone who is awake, but taken by surprise, see Don't Sneak Up On Me Like That.

Examples of Wake Up Fighting include:

Anime and Manga

Hunny in Ouran High School Host Club does this a few times.
Happens in Gunsmith Cats, in the hospital: a mook is trying to plant a bomb under Rally's pillow (where she also kept her gun), Rally instantly snaps to alertness and shoots the mook. Mook runs off and jumps into his car. Rally notices the bomb and tosses it out the window... onto the mook's car. And we later learn through all this, she wasn't even fully awake.
In Trust & Betrayal Tomoe drapes a sleeping Kenshin in a blanket. She gets a katana drawn and placed inches from her neck for her trouble.

Film

Lethal Weapon
Gladiator: Maximus wakes up armed with a small dagger in his hand.
Happens twice in Anastasia.
Wolverine does this to Rogue in the first X-Men 1 movie, however goes too far and instinctively stabs her in the chest.
Overlapping with Catapult Nightmare, Aragorn in the movie version of The Lord of the Rings.

Literature

In Alex Garland's novel The Beach, one character talks in a very pissed off manner about a time when another character was nodding off to sleep. There came a slight noise in the bushes, and he leapt up with his knife.

"He wanted me to see how fucking alert he was."

In Harry Potter, Harry warns Ron against visiting Moody first thing in the morning, for fear that Moody will respond this way.
In The Hunger Games, Haymitch often sleeps with a knife in his hand, due to his experiences in the Games.
Most characters react this way in the brief moment between waking up and being awake enough to think properly. In The Colour of Magic Hrun the Barbarian is apparently so used to people trying to kill him in his sleep that he reacts before he wakes up:

Hrun made a glubbing noise, turned over, and slept on.
With a careful movement, as though handling some instrument of rare delicacy, the woman drew a slim black dagger from her belt and stabbed downward.
Before it was halfway through its arc Hrun's right hand moved so fast that it appeared to travel between two points in space without at any time occupying the intervening air. It closed around the woman's wrist with a dull smack. His other hand groped feverishly for a sword that wasn't there ...
Hrun awoke.
'Gngh?' he said, looking up at the woman with a puzzled frown.

At least one of Redwall's Badger Lords has done this. One of his hares had come in to wake him, right as he reached the end of a nightmare about his sworn enemy. The result was a Catapult Nightmare complete with a battle cry and a sword hacked straight through a shield. The hare was unhurt, but shocked.

Live-Action TV

In the Doctor Who story "Image of the Fendahl", the Doctor wakes his companion Leela and she pulls her knife on him. She wouldn't normally overreact that badly, but she'd been having nightmares because of the baleful influence of the Fendahl.
Parodied in 30 Rock. Tracy warns Liz that he has Bad Dreams, but not to wake him or he will attack her.
When alarmer, NCIS's Tony, Ziva, and Gibbs have all been shown to leap for a weapon/punch.
A Sitcom thirty or forty years ago had a commando veteran visit the main character's place on a date. Unfortunately, he'd just had to spend an unusually long time without sleep, so he kept dozing off just sitting there—and every time she tried to rouse him, he'd come awake frantically lashing out with karate and destroy another piece of furniture....

Web Comics

This is the reason no one tries to wake up Bun-bun in Sluggy Freelance.

Web Original

In The Adventures of Dr. McNinja, Sidekick Gordito is afraid of waking up Dr. McNinja for this very reason.
- Gordito himself is often subjected to literal rude awakenings; the Doc only seems to drop him off at his parents' house when he's asleep, leaving him to wake up startled in strange and often dangerous conditions.