Drifting Classroom

A very dark manga (original title: Hyoryu kyoshitsu) by Kazuo Umezu. It was first published in 1972 and later made into two different live-action movies: A Japanese one in 1987, and an American one in 1995.

Sho Takamatsu's day started out bad. He overslept, found his mother had thrown out all his toys, didn't eat breakfast, and left home after getting in a screaming argument with his mom. After arriving at school, class began, and then the school was teleported into a post-apocalyptic desert wasteland.

Also this is an elementary school, and Sho himself is in the 6th grade. And the students have no special immunity to things like starvation, crushing, or psychopaths with crossbows.

Things quickly get bad, as the psychotic delivery man Sekiya takes the food hostage and begins killing students. Then one of the teachers has a psychotic break and wipes out the other adults, then begins killing students. And then... well, let's just say that Kazuo Umezu thinks of a great many ways to kill the students. It doesn't help when they find evidence that they've been teleported into the future and that the world has been completely turned to desert. Or that there does not seem to be any food other than what was teleported with them, and that everything in the world seems calculated to kill them.

Meanwhile, back in the present, Mrs. Takamatsu pines for her son. When she starts receiving psychic messages from him, can she give him enough help to survive in his barren environment?

Tropes contained include:

 * Adults Are Useless: The principal is a complete idiot, Sekiya is pure evil, and  kills all the others and then begins running over students in his car.
 * After the End
 * Annoying Arrows: The bug monster is able to withstand a crossbow bolt that appears to be made from half a tree.
 * Anyone Can Die:
 * Authority Equals Asskicking: Sho is elected President, and is probably the strongest of all the students. He wins all his fights and outruns everyone near the end.
 * Big Eater: Nakata. Done seriously, unlike the usual comedic usage of this trope. Not only do they have very limited food, but his eating powers the monster he summons.
 * Body Horror: What happens to those who eat the evil mushrooms...
 * Chekhov's Gunman: The offscreen thief in the first volume turns up a lot later. In a gruesome manner.
 * Children Are Innocent: Averted.
 * Creepy Child: Scar Kid, who decides to kill everybody because he's been infected with the Plague. Also Princess, after she returns from her journey, and all the children near the end once
 * Deconstruction: Hey, remember how in Lord of the Flies, everything was pretty much okay until the kids themselves became evil? This series purports to show what would really happen if a bunch of kids were left by themselves outside of civilization. Nature fights back.
 * Diabolus Ex Machina: Starts sometime in volume 2, when the kids discover they got the world's most evil delivery man. Keeps ramping up (they also got a psychic who can summon monsters without realizing it, and a black-plague infested squirrel). Continues through pretty much the whole series.
 * Disability Superpower: It turns out that Nishi, who is on crutches, is the source of the psychic link between Sho and his Mom.
 * Driven to Suicide: A teacher slits his own throat after he says he can't take it anymore, and several small children jump to their death as they want to go back to their parents.
 * Everyone Calls Him "Barkeep": Princess is never given another name. Some kids, like Scar Kid, are never named at all.
 * Everythings Nuttier With Squirrels: Terribly subverted.
 * Everything Trying to Kill You: And how!
 * Face Heel Turn:
 * Faux Action Girl: Averted, in that Sakiko actually does stuff, although not as much as the others.
 * Five-Man Band:
 * The Captain: Sho.
 * The Lancer: Ikigaki.
 * The Smart Guy: Gamo.
 * The Big Guy: Otomo.
 * The Chick: Sakiko.
 * Hammerspace: How did Mr. Takamatsu put enough streptomycin to cure 400+ students in a single package in a single mummy?
 * Heel Face Turn:
 * Hide Your Children: Brutally subverted.
 * Hope Spot:.
 * I'm a Humanitarian:
 * Infant Immortality: Subverted and played straight. Plenty of children die, but
 * It Got Worse: Whenever they solve one problem, another immediately develops. An example incident is when they finally get it to rain, the water turns the sand to quicksand, killing some of them, and is powerful enough to decapitate/tear apart some other students. And when they survive that, the evil mushrooms grow. Etc.
 * Karmic Death:
 * Kill It with Fire: Scar Kid's plan for dealing with the black plague.
 * Knife Nut: Otomo gets into several knife fights as the series continues.
 * Live Action Adaptation: The 1987 film.
 * The Load: Nakata. He eats too much, he whines, he summons a giant monster that kills and destroys, he summons even more monsters that kill and destroy. Considering that so many kids die routinely anyway, it is quite annoying that Sho defends him and criticizes the kids that are relieved.
 * May Contain Evil: The mushrooms.
 * Meanwhile in the Future: The storylines involving Sho's mother generally work this way to some degree, as Mrs. Takamatsu seems to hear Sho's cry for help only at certain times. In the black plague arc, she could just wait in the hospital until she was ready. Gamo likens this to the kids taking a bullet train through time for a while before getting on the regular train while their parents stayed on the regular train the whole time, meaning that the two timelines should be synchronized after the time travel.
 * The Medic: Yanase.
 * New Powers as the Plot Demands: The rules on the psychic link between Sho and his mom are pretty consistent, but other magic, like Nakata's powers, seem pretty random.
 * Retirony: Oki.
 * Sacrificial Lamb:
 * San Dimas Time: Averted; see Meanwhile in the Future.
 * Sanity Slippage: Shu's mother is portrayed as undergoing this throughout the series, acting increasingly disturbed as the series progresses. Depending on how you view it  If you subscribe to this theory, then
 * The Starscream:
 * Tagalong Kid: Yu, the preschooler.
 * Teenage Wasteland: Though most of the kids are a little bit younger. The lyrics of the Who song are unbelievably apt, though.
 * The Many Deaths of You: Rare non-videogame example. Umezu comes up with many original ways to kill the children. Falling off buildings, dying of sickness, eaten by giant invincible bug thing, eaten by swarm of little invincible bug things, drowning in quicksand, decapitation by water, mutating into beasts, eaten by giant starfish, dying of starvation, dying of black plague, burned to death by classmates, killed by decaying robots... and there are more. Plenty more.
 * Too Dumb to Live: Several times!
 * Voodoo Shark:
 * Apparently you can be mummified and left indefinitely in the hospital morgue. All you have to do is ask.
 * Wise Beyond Their Years: They may just be kids, but they act responsible and adult pretty fast.
 * World Half Empty
 * Wise Beyond Their Years: They may just be kids, but they act responsible and adult pretty fast.
 * World Half Empty