Pinned Down

"""Gordon, I can't move! These snipers got me pinned down!""

- Barney Calhoun, Half-Life 2

A situation where a character or party is pinned down by enemy fire and can't fight back, or sometimes even move, without getting their heads shot/burned/ripped off. This can prevent them from getting to an injured ally the character or group needs to help, stop a shorter-ranged character from getting within range of fighting back, or simply keeping the heroes from moving forward, buying a villain time.

A variant is "cover fire", which means pinning down an enemy when an ally moves forward (usually to the next safe spot, before firing in turn so you can move).

It's often used in video games as well. Ever wondered why enemy soldiers keep shooting at where you last emerged from cover? They're keeping you pinned, probably while they recharge their shields or move into a position where they can kill you.

If it's being used to keep allies from helping a character who is able to fight back, the allies are Locked Out of the Fight.

Anime and Manga

 * Mahou Sensei Negima: This happened to the heros during the School Festival's third day when they were trying to make it to the battles grounds. Mana had One Hit KO rounds that send anything they touch forward in time to the battle's end (which they've presumably lost), and when they tried to hide in a trolley, she shot the trolley itself, sending the entire vehicle to the future. They managed to escape when Negi used his own Magitech Time Machine to escape the in the last second. Kaede stayed behind to hold off Mana while the rest went ahead.
 * Parakewl and Mauchi tried this during Tower of God's Hide and Seek test on Quant. Keyword is tried.
 * Funnily enough, Hatsu, who before managed to hold Quant down for a few seconds, relied on them to do exactly this with their javelins, but they simply ran away.
 * Used to great effect in Monster. In the anime, Grimmer ends up in a situation with a cop lying on the ground bleeding with him unable to help due to a sniper. As time goes on, the foreign language the squad is using gets to Grimmer and Probably should have kept that sniper in place.

Comic Books

 * Sin City has The Babe Wore Red which shows Dwight getting pinned down by a sniper while rescuing the eponymous Lady in Red.
 * Wallace was also pinned by a sniper in Hell And Back. He got out of that situation pretty quickly, though.

Film

 * In Full Metal Jacket, the squad is pinned down by one sniper. It isn't pretty. Especially since it tries them to get out of their cover by repeatedly shooting an injured but still alive squadmate.

Literature

 * Generally, every gun fight in Matthew Reilly's books. This is the most common form of gunfire used in his books, except when he breaks out the Improbable Aiming Skills at least.

Tabletop Games

 * Shadowrun had rules for suppressive fire (anyone in the target area who emerges from cover gets hit).
 * Warhammer 40000 has a mechanic regarding this, but it requires more than mere rifles - weapons with the pinning mechanic tend to be heavy ones.
 * GURPS requires only a moderate rate of fire to use suppression fire but without an Ro F of around 20 (attainable only by a very few weapons) reliably hitting targets is virtually impossible.

Video Games

 * This can happen in first and third-person shooters, but in multiplayer, most players won't be waiting in their cover for their death to come and there is rarely a system to ruin players under heavy fire, so thinking an enemy player is suppressed may lead you to just running up and getting shot by them.
 * In Metal Gear Solid, Meryl is wounded by Sniper Wolf. Snake can't get to her to help and can't get close enough to Wolf without getting his head shot off. He has to abandon Meryl and double back to grab the sniper rifle.
 * Gordon Freeman rescues Barney Calhoun in Half-Life 2 when he is pinned down by snipers.
 * Brothers in Arms: Basically a First-Person Shooter, except it relies heavily on being able to successfully utilize this trope on the enemy. If you can't manage to keep their heads down, they'll kill you.
 * Tactical Shooters as a whole often implement this trope as an important game mechanic that must be taken advantage of (and/or watched out for).
 * Jagged Alliance 2 has recently received the ability for suppression fire in its 1.13 unofficial patch.
 * Mentioned in dialogue, but not actually a mechanic in End War. Units under fire while at half health are described as being suppressed by your XO and their info tab, but it really means nothing more than being at half health (on the other hand, any unit at half health probably has little chance against what they're fighting anyway)
 * Warhammer 40000: Dawn of War II has the Suppression mechanic. Regular ranged units tend not to be capable of it, but heavy weapons will if they don't just kill all infantry in their firing arc, and there are a few other options to inflict this with other units. Being suppressed greatly reduces weapon firing times and slows movement speed, but there are ways to break it, namely the Retreat button.
 * Full Spectrum Warrior uses covering fire as a primary gameplay mechanic, and makes a distinction between ordinary fire (most weapons) and suppressing fire (vehicles and mounted machine guns). Your teams can do suppressing fire too, completely pinning down any targets, but burning through ammo quickly.
 * Introduced in Project Reality, this feature made it to Battlefield 3. Getting pinned down by auto weapons or sniper fire will blur out your vision and disables your Regenerating Health, even if you did not get hit. Killing a suppressed enemy will also give suppression assist points to the suppressor.
 * This is a major gameplay element in Company of Heroes. There are two levels - suppressed and pinned. A suppressed unit moves very slowly but gets a slight evasion bonus from being prone on the ground, and a pinned unit is completely immobile and unable to fire. Since cover only provides a bonus while it's between the users and the fire, any unit suppressed is waiting to be outflanked and killed (so press Retreat for that unit). Heavy machine gun weapon teams can be used to supress infantry units, which dramatically slows their movement and reduces their firepower. That being said, all weapons' fire will suppress any infantry that survives long enough (unless they are in a building).
 * Armed with a Bren gun, the British Infantry Section can 'button' tanks and other vehicles - it will greatly slow the vehicle down and greatly reduce their ability to see, which is described as the infantry section firing at the vehicle's sight ports. The vehicle is a sitting duck to being outflanked with anti-tank weapons and can't defend itself while alone and buttoned down, but having other allies near them will allow them to fire back since they provide sight for the vehicle.
 * The 2010 Medal of Honor features this as a gameplay mechanic for one or two missions, complete with a helpful icon that appears to let you know you have successfully suppressed the enemy machine gunner (for a few moments, anyways).
 * In Halo the Covenant will keep firing at the last position they saw you since you last ducked behind cover. Trying to re-emerge there will probably get your shields shot off in short order, but if all their focus is there...
 * An important part of gameplay in Battlefield 3, where shots that hit within a certain radius of a player cause them to become suppressed, distorting their vision, stopping health regeneration, and reducing their accuracy. Under certain circumstances you can even get more points for doing this than for an outright kill.

Real Life

 * Formally, this situation is known as being "under suppressive fire". Achieving this to enemy targets and getting closer to shoot them with impunity is the main tactic to neutralization for infantry (and a heavy contributor to A-Team Firing, since soldiers trying to achieve it really don't mind not hitting any enemies while doing so).
 * Suppressive fire doesn't always require fully automatic weapons, soldiers sometimes drill to suppress by having multiple people fire single shots. This is partly a result of logistical concerns, encouraging soldiers to use the full automatic setting wastes ammunition.