Absurdly Ineffective Barricade

Uh, nice barricade, but the door opens the other way.

When characters attempt to physically seal off access to a room, passageway or building, but are doomed to fail miserably due to poor choice of materials or bad tactical planning.

This trope can come in many flavors. A person on the run from a killer may choose to block a door with light and easily movable objects. Other times, Myopic Architecture can easily come into play; characters may put a serious effort into blocking a single door in a room with multiple exits and/or easily breakable windows. In comedic situations, the ineffective barricade may come in the form of what amounts to a (quite surmountable) waist high fence, or the character in question could simply forget that the door he's trying to block opens outward instead of inward.

This can also be seen when multiple characters are making serious attempts at fashioning a barricade of some sort, while one of their companions piles on extremely light objects like pillows or potted plants or else is steadily deconstructing their barrier in order to make his own. Occasions like these can at times serve as a lesson to not allow the Cloudcuckoolander to assist in defense planning.

A common comedic situation tends to occur where the barricade is being built, but the builders turn around and find that they have sealed themselves inside with what they were trying to escape. Sometimes the thing they were trying to escape may have even helped them construct the barricade while they weren't looking. Either way, Hilarity Ensues. The Rule of Funny aspect of this trope is really played up, however, when what is an obvious Absurdly Ineffective Barricade is shown to actually work. In these cases, the barricade builders are often just as surprised as anyone else.

While the Absurdly Ineffective Barricade is often Played for Laughs, it can sometimes be used to show the effects of panic on a terrified character on the run. In the latter cases, the poor choice of defenses will often lead to the realization that the builder has made a fatal mistake... moments too late to do anything about it, of course.

Note that in order to qualify as an Absurdly Ineffective Barricade, there must be some obvious flaw on the part of the characters making it. If the defenses are well planned but the villain is powerful enough to burst through them anyway, it does not count.

A subtrope of Rule of Funny. Contrast Berserk Board Barricade, Insurmountable Waist High Fence and Great Wall (although a Secret Path through a Great Wall can turn it into an Absurdly Ineffective Barricade).

Examples of Absurdly Ineffective Barricade include:

Film

In Dead Air, after the crew of a late-night radio talk show realizes that their building is smack in the middle of a Technically Living Zombie Apocalypse, they all decide to start barricading the doors to their studio. While the male crew members are stacking up heavy tables and filing cabinets, the show's producer contributes by setting a small potted plant on the pile.

Logan: Lucy... and what exactly is that supposed to accomplish?
Lucy: (walking off) Fuck you!

In Scary Movie 3, the heroes are shown boarding over a cellar door to keep aliens out (in a parody of Signs). Cue Cindy opening the door with no problem. It turns out they'd just nailed some planks to it without fastening them to the wall.
In The Big Lebowski, The Dude suffers multiple home invasions, and getting kinda sick of it, starts to nail a piece of wood to the floor and props a chair between it and the door. Like in the Scooby Doo example below, it is later revealed that the door opens outwards. After this, The Dude trips on the piece of wood he nailed to the floor every time he comes home.
In Signs, the family barricades all the doors and windows downstairs. Realizing they don't have enough wood to barricade all the upstairs windows, they instead barricade the doors of every upstairs room with a window. It's only after the aliens break into the attic that the family realizes they forgot to barricade the attic door.
- Another example from the same film, this time played for laughs: After the family flees to the basement, they need to block off the coal chute. One of the characters does so with several heavy bags of dog food; as he sits against the barricade out of breath, he notices a small can by his leg, which he puts on top of the barrier.
In Candleshoe, the group does the usual "toss the villains out and move the furniture to block the door" stunt, but the baddies reappear through the open door at the opposite end of the room.
Jim Carrey sealing the gate to Landfill Park in The Mask is a great example of this. As he leaves the park, he puts an intricate lock to keep two cops inside... only to notice a large police force outside!
The Three Stooges shorts used this in a couple of varieties, including the door opening outwards and the villains coming in behind them, sometimes handing them things to put on the barricade.
In Twenty Eight Weeks Later, a safe room turns out to have a back door.
In one of the Hilarious Outtakes of The Lord of the Rings, while preparing for battle in Moria, the Fellowship goes and braces the door to Balin's Tomb with axes, polearms, and whatever's around. Orlando Bloom/Legolas makes a big show of sticking one staff up against the door. Ian McKellen/Gandalf then walks up to the door in apparent disbelief at Legolas's "contribution", nudges the staff—easily knocking it over—and scoffs, calling it "typical elf work."
In UHF, Stanley Spadowski (Michael Richards) is being chased around the offices of Channel 8 News by the top exec's murderous thugs. He shuts himself into the top exec's office and barricades the one door with everything he can find, until the door is completely covered. He then collapses in exhaustion, but is proud of his quick thinking. They'll never get him now. The thugs then come through the conveniently large window.
In The Last Lovecraft our "heroes" are trapped in a small RV, when one of the monsters from the deep smashes through the window all they can do is close a flimsy fold out wooden screen to slow it down.
In Abbott and Costello Meet Frankenstein, the duo attempts to keep the rampaging monster out of their refuge by pushing a heavy bed up against the door. Unfortunately, the door opens the other way...
- They also once tried to barricade a door with their own bodies, in the end it didn't work...because there were no walls.
In The Mummy Returns, Evelyn tries to barricade a museum door by pulling a park bench in front of it, but it's ineffective because "these guys don't use doors." The mummies just charge through the walls to get out of the museum.
Jay and Silent Bob Strike Back: during the chase around the Miramax lot, the titular pair place a small trash can in front of one of the doors before fleeing. Although to be fair, one of the security guards does smack his shin into it and limps around for a moment.
In Howard Hawks' The Thing from Another World, they barricade a door against the monster, but the door opens the other way.

Literature

Happens to a elderly wizard in Discworld, he knows that he is going to die soon so he makes a chest that is magically sealed against Death. However, as Death helpfully points out, he made it airtight.
In 1812: The River of War, some of the soldiers defending the Capitol Building rip the doors off of one entrance to use them as material for barricading another entrance. After the stupidity of this is pointed out to them, they fix it by dragging two enormous statues to block the now empty doorway.
In the non-fiction book On Wings of Eagles the protagonists, U.S. businessmen escaping from the Iranian revolution, are in a van that's stopped at a revolutionary checkpoint. One man whispers, "Quick, lock the door!" causing his companion to repress some hysterical laughter, as the revolutionaries are armed with assault rifles that can easily shoot through the entire van.

Live-Action TV

Buffy the Vampire Slayer: In the episode "Bewitched, Bothered, and Bewildered", after a spell gone awry has caused every girl in the school aside from Cordelia to fall madly in love with Xander, he attempts to take refuge in the school library by moving library card catalog in front of the double doors that serve as the entrance. Since he apparently didn't realize that the doors open outward, Buffy in a coat (and not much else) calmly opens the doors and walks around the catalog while Xander's back is turned.
In one episode of That '70s Show Hyde does this. After it looks like Laurie is moving out and he's getting her room, she ends up staying. The end of the episode shows him standing there with the dresser up against the door telling her that she'll never get in. Cue Red opening the door outward.
Monty Python's Flying Circus: during the "Upper-Class Twit of the Year" sketch, one of the competitions in the obstacle course is to jump a wall composed of matchboxes. The wall is three matchboxes high(roughly half a foot). Subverted in that the Twits do end up taking a while to clear the jump.
Doctor Who: In Destiny of the Daleks, the Doctor and Romana take refuge behind a hastily cobbled together privacy screen. The Doctor says something like There, That Should Keep Them Out, and Romana sneers "That wouldn't keep out a determined mouse!"

Theatre

In A Very Potter Musical, a group of students led by Ron barricade the door to keep out Voldemort. Because it's a play, there's no wall, just a doorframe in the middle of the stage. Voldemort walks around it. And then kicks the barricade.

Video Games

In the original version of Ao Oni, Megumi barricades herself in a room with most of the furniture. It looks effective at first glance... but Hiroshi can easily shove the ottoman blocking off the doorway aside, giving him room to slip right past her defenses. Good thing he's able to lock the door.

Web Comics

Problem Sleuth: "...before you can pry any [boards] off, the door swings open, away from the boards. It seems the boards never actually served to obstruct the door in the first place."

Western Animation

Many episodes of Scooby-Doo involve the gang building a barricade, only to discover the door opens outward as opposed to inward. On at least one occasion, Shaggy and Scooby do this, and they don't immediately realize that the monster they're escaping entered from the opposite side of the room and is helping them build the barricade.
- In "Mystery Mask Mix-Up", the wall the door was in turns out to be movable, leading Shaggy to quip, "Wouldn't you know he'd be coming through the wall..." Also averted in "Spooky Space Kook" where Shaggy realizes a pile of chairs isn't going to hold the monster back and suggests that Scooby should try something else. It was played straight previously in the episode though.
- A hilarious subversion of the 'sealed yourself in with the monster' situation, when Shaggy reveals that by removing a single item, the whole barricade collapses, allowing the gang to escape.
In The Simpsons, when a hurricane is approaching, Homer removes the back door of the house and nails it over the window, leaving the doorway without a door. It doesn't work very well.
In Camp Lazlo, the Jelly Bean Scouts barricade the cabin door with planks to keep the Squirrel Scouts out. It's revealed that they took the planks from the back wall of the cabin, leaving a huge hole for the Squirrel Scouts to get through.
In the Ed, Edd 'n' Eddy episode "Home-Cooked Eds", the Eds try to barricade themselves in Eddy's house to keep out the Kanker Sisters, who have decided to take a vacation on Eddy's front lawn. Yet the Kankers somehow get into Eddy's house anyway.
In a clip from 1935 called Little Black Sambo seen here, the titular character and his dog are trapped in their house by a tiger. They start piling up chairs and such in front of the door to keep the tiger out-but the tiger simply ties a rock on a rope to make it sound like he's still pounding on the front door, climbs in a window, and watches them continue building the barricade without even noticing him for a while, even handing the dog a few items to add to it before they realize he's inside with them.
In the Looney Tunes Brother Brat, babysitter Porky is fleeing a vicious axe-wielding baby. He shuts himself behind a door and rapidly barricades it with every object in the room - including the waiting baby.
In South Park‍'‍s episode "Butt Out". Believing Kyle is going to sneak behind his back to steal the commercial position for the Anti-Smoking team, Cartman sneaks into Kyle's house to nail his bedroom door at night. It turns out not only was Kyle just getting back to his room after getting a glass of water, but the door opened the other way. This still didn't stop Cartman from boarding up the door once Kyle went into his room.
Done in The Amazing World of Gumball episode "The Fight", when Gumball and Darwin are escaping Tina.

Real Life

In Somalia US troops decided to use the much-vaunted 'sticky foam' to create a barrier against rioters. The Somalis watched in some puzzlement as the strange substance hardened into a barrier…then they just climbed over it.
In Port Arthur, a Victorian era prison town in Tasmania, there is a very impressive gatehouse to the military barracks. Which you can bypass completely by going around the corner and stepping over a half metre high wall. (Yes, it was so back then, too.)
Former American President Donald Trump's "big beautiful wall", which he promised to build along the entire length of the United States' southern border to stop illegal immigrants from coming north. Only a few hundred feet of it were ever built (and that only as samples of possible forms it could take), which began collapsing from inferior materials and substandard construction before his term in office ended. Plus, as more than a few commentators noted, every proposed design provided no hindrance to tunneling. Not to mention most illegal immigrants come in via automobiles and airplanes -- not by foot over empty land.
- In 2022, Doug Ducey, the outgoing Republican governor of Arizona, ordered a wall built of shipping containers on Federal land along the border between Arizona Mexico. Intended more as a PR move and a slap to Trump's successor Joe Biden than anything else, this "wall" was riddled with huge gaps where containers could not be made to line up properly, and numerous photos were posted on social media of people walking through it or clambering easily over it. About a third of it was built before the Feds sued and had the project canceled; in the end it cost close to $200 million of taxpayer money to put up and take down.