A vision of paradise that is anything but that — to the average observer, anyway. However, some people in fiction have built their religion around an idea of paradise that might seem a little... off to outsiders (to say nothing about some people in reality).
Not all shady cults and religious nuts belong in this category. If someone believes the god they are trying to summon is going to bring on a new era of hugs and puppies, only to discover to their horror that all it does is unleash mayhem and rain of fire upon the world, it's not this trope. However, if the person knows from the start that their god is going to bring mayhem and rain of fire in its wake, but sincerely sees this as the epitome of ultimate bliss, then you have an Infernal Paradise.
Most instances of Warrior Heaven are this for non-warrior cultures (who may mistake it for Hell Is War). Contrast A Hell of a Time and Hell of a Heaven.
In Secret Six, Catman's parents are both dead, and he meets them both on a visit to hell—his abusive father chained up, and his mother a lioness. When he questions Etrigan about why his mother isn't in heaven, Etrigan states that one chooses their heaven, and his mother's heaven is being his father's tormentor in hell.
The Cenobites' dimension in Hellraiser. A dimension where pain and pleasure are synonymous. they even lampshade it themselves, like when Pinhead describes himself and the other Cenobites as "Angels to some, demons to others."
In fact they are usually summoned by someone "seeking the pleasures of heaven or hell, it doesn't matter which". They tend to change their mind about how much like a paradise that sounds after a couple of decades.
At least one Speculative Fiction story ("Desertion") does this for the surface of Jupiter. In this story, people turn themselves into native lifeforms to explore inhospitable worlds and it works great until people stop coming back from exploring Jupiter. The hero heads out to see for himself where everyone has been going and it turns out that being a Jovian rocks so hard that their explorers don't want to come back.
In the satirical short story "Heavens Below - Sixteen Utopias" by John Sladek, one of the Utopias is a family picnic in a garbage dump, with the family eating the garbage as if it was a heavenly feast.
In one of his short stories, Mark Twain deliberately invokes this: the protagonist finds himself in the heaven of an alien race, which is full of beer, women, and song. He is horrified — he wanted to go to Fluffy Cloud Heaven. He and the aliens each see the other's idea of heaven as this trope.
In Letters From the Earth, Twain's Satan writes back to the other Archangels about how crazy Man's heaven is, clearly portraying it as an infernal paradise. It consists of an incredibly boring endless praise service for the Abrahamic god (as opposed to the Creator Satan and the other Archangels actually served). Here, everyone sings even though most of us are terrible at it, everyone is in an endless prayer service though most humans view church as a terrible chore, everyone has to play music though most of us are bad at it, no one can exercise their intellect though all humans long to, and worst of all, no sex.
In The Wheel of Time, most of the Darkfriends, Black Ajah and even the Forsaken are following the Dark One because of the "promised rewards" they think they'll get once the Dark One takes over (you know, power, getting to rule the world, etc.). Ishamael seems to be the only one who serves the Dark One knowing that once the Dark One gets out of his prison and takes over the world, he will destroy the world and everyone in it.
In Heaven by Ian Stewart and Jack Cohen, planets having been assimilated by the religion of Cosmic Unity have been turned into "Heavens". These look extremely squicky to outsiders, because every — still living — inhabitant has been disassembled and their parts blended together for ease of storage, so that you get rivers of blood and the like. However, the combinations of parts that make up individuals are still being kept track of and their minds exist as wholes within a paradise-like virtual world. Nevertheless, it's ultimately presented as not such a terrific way to be.
"A Song for Lya" by George R. R. Martin presents an alien world where the locals, the shkeen, live in medieval squalor, with no advancement of any sort for thousands of years. They also host disgusting parasites called "greeshka" which shorten their lives and retard their intellects. However, when "Joined" beings die, their minds are preserved in a psychic union which is so pleasant that just the telepathic spill-over to the living Joined is enough to make them indifferent to achievement and personal hygiene; they join this "Union" by going into a network of caves outside their sacred city, finding a giant greeshka, lying down on it and waiting for it to consume them. The bad part is presented as being the shkeen belief that anyone who does not die in the Union is utterly alone. A psychic couple, Rob (the narrator) and Lya (for whom the story is named), are summoned to the planet to find out why the religion is starting to get numerous human converts, and they discover that each of the "Joined" are truly happy and love everyone, even total strangers, as strongly as a married couple would love each other. This convinces Lya to join their cult and put herself on the fast track to Union. Her psychic calls to Rob to join her in the Union are waved off by the planetary administrator as being some kind of "psy-lure" but it's left ambiguous.
As I was walking among the fires of hell, delighted with the enjoyments of Genius; which to Angels look like torment and insanity. I collected some of their Proverbs: thinking that as the sayings used in a nation, mark its character, so the Proverbs of Hell, shew the nature of Infernal wisdom better than any description of buildings or garments.
A recurring characteristic of vampires and demons in Buffy the Vampire Slayer and Angel is their desire to bring about Hell on earth, releasing the Old Ones. This seems particularly nonsensical for vampires, who require mortals to feed on to stay sane. It's probable they think they'll be rewarded in the new order, which given the capacity for gratitude the Old One seen in the series demonstrated towards its summoner (i.e. not making any attempt to save him when he was killed, nor caring that he was) seems unlikely. It doesn't even appear to be a trait of the transformation, because when Angelus met The Master and learned that he considered the purpose of vampires to be worshiping the Old Ones, ceasing only to feed, he promptly decided Screw This, I'm Outta Here.
Lampshaded and Subverted when Spike decided to help the good guys save the world, because:
Spike: We like to talk big, vampires do. 'I'm going to destroy the world.' It's just tough guy talk - strut round with your friends over a pint of blood. The truth is I like this world. You've got dog racing, Manchester United, and you've got people - billions of people walking around like Happy Meals with legs. It's all right here.
Funnily enough he was saving the world from Angelus, who had the conversation below shortly after he was turned. Either the centuries brought him around, or he took the whole soul incident pretty hard.
The Master: Awaiting that promised day when we will arise, ARISE, and lay waste to the world above.
Angelus: Why'd you want to do that?
The Master: Huh?
Angelus: Well, I mean have you been above lately? It's quite nice.
Makes sense. Angelus was largely depicted as "evil for evil's sake", and he just went further down that rabbit hole. Spike was largely depicted as "Evil for love" and later "Crazy for love" and later "Batpoop insane for love". So it makes sense that he'll "talk the talk" but when it comes time to destroy the world, he has no real personal motivation.
Call of Cthulhu. Cthulhu Mythos cultists know that if the Mythos deities are let loose in the world it will lead to Hell on Earth, but they try to bring it about anyway because they're totally insane so hell on earth sounds wonderful to them.
Mage: The Ascension. The Nephandi have a thing of willingly wanting to bring destruction to the world, and in the case of Malfeans, want to help the Wyrm turn it into an eternal, rotting hell, similarly to their Black Spiral Dancer counterparts
As mentioned above, the Black Spiral Dancers. They believe that the Wyrm was driven mad by being trapped in the warp and weft of reality by the Weaver (technically correct), and thus the best way to serve the Wyrm is to spread enough corruption and decay that the bonds loose and their (now completely batshit) lord and master can get loose. Whereas Gaian werewolves have sacred places that are effectively glades and oases, Black Spiral Dancers like to commune in toxic waste pits.
Exalted has the whole hierarchy of death (the Neverborn, their Deathlord servants, and the Abyssal Exalted) directed to follow the idea that the complete Cessation of Existence that would come about by feeding all of Creation into Oblivion would bring about eternal peace and bliss. This is mainly because the Neverborn themselves have been dealing with flesh-eating bacteria of the soul for millennia on end, and can't pass on as long as Creation exists to fetter them to it. And even then, many of their Deathlord servants are in it for their own ends, with only three really preaching the blessed peace of Oblivion.
This is also a strong theme of Cecelyne, the Endless Desert, one of the Yozis, and thus passes on to her Infernal charges via her Charm set. As she wants those who follow her to be priests of a gospel of the strong over the weak, many of her Charms rely around the creation of holy lands (by inflicting desolation on an area) and the production of manna from heaven (in the form of delicious locusts that will turn anyone who eats enough of them into a creature of darkness).
Some of the Outer Planes in Dungeons & Dragons (where souls go after death) can be like this, since there is at least one for every Character Alignment (and they are accessible by mortals through Plane Shift and similar spells). The Heroic Domain of Ysgard probably isn't everyone's cup of tea, being basically a giant battlefield where everyone fights endlessly, only to come back to life every day. The Norse would have loved it. Olidammara's realm is an eternal party filled with wine, women, and song, but probably wouldn't appeal to a straitlaced paladin very much. Elysium is so pleasant that it's impossible not to feel good while you are there...but you will eventually lose your memories, and many would rather avoid that.
Even some of the bad afterlives are acceptable to their inhabitants. Kobolds are the Butt Monkeys of the universe, and their afterlife (assuming they worship the evil Kurtulmak) would seem to reflect this; they are packed in like sardines in a giant hot cave, with little room to move, which would be an And I Must Scream eternal fate for most. The kobolds like it fine, however; they are safe and never hungry, which is better treatment than most of them got while alive.
Plane Scape's Beastlands could definitely fit this bill, despite being considered Neutral Good. The dead are reincarnated as animals and "nature red in tooth and claw" is exaggerated for Black Comedy. The reborn animals retain their sapience. Anyone want to sign up for the life of a sapient rabbit or other prey animal just waiting for some other intelligent being to hunt you down for dinner?
Crazy cultist Claudia in Silent Hill 3 is convinced that the deformed monsters, bleeding walls, rusting landscape and all the other lovely things the Dark World has to offer are a beautiful example of God's love and the wonderful paradise she's building. Vincent responds with the above quote. Word of God has said that everyone's vision of Otherworld is different, and the player only ever sees it through the main character's eyes. It's likely that Claudia, at least up until that point, really was seeing paradise. Which, if you think about it, is actually kind of sad.
The Mana cult in Siren has an unique take on the whole ever-lasting life thing. Not everybody involved knows just how sinister their religion actually is, but the various religious objects you can collect in the game still paint a rather creepy image of the paradise these people yearn for.
The demons from Disgaea would have you believe that their worlds are like this. Given that the cinemas describe seas of sulfur, hordes of terrible monsters and Home-Ec classrooms that you may never return from, they might have a point.
A more subtle example: as part of a deal with The One King, Valfred and his followers in Suikoden Tierkreis aren't erased from existence when the One King is summoned, instead living in the "one true world" of perfect order. The heroes actually get to see this world, and it's a "Groundhog Day" Loop of each person's perfect day. But that's not this trope. What's this trope is when they realize that their memories don't match, and they can't all have lived the same day. Then they see this "paradise" from the outside, as those in it blindly wander through the ruins of the normal world, hallucinating the presence of their friends and family. And Valfred knew it was all an illusion—he simply could not let go of the family he lost, and he was willing to sacrifice everything and everyone for their imaginary resurrection.
Geist. The main antagonist describes his plans involve blotting out the Sun, boiling the sea, and setting fire to the landscapes, turning it into a "paradise".
The Mythic Dawn's afterlife in The Elder Scrolls IV: Oblivion is called "Paradise" but is actually quite hellish for the formerly human residents. A few of them do seem to like it there; most don't.
A point of conflict among werewolves in Skyrim is that they are destined for the hunter's paradise instead of the warrior one. A few are looking for a cure to fix this, others count it as a benefit.
The Void is a bleak, purgatory-like realm on the brink of destruction. TheBrothers call it their heaven, and not unjustly so, given that they come from the Nightmare, an even more hellish world. On a grander scale, every Limit is heaven to the ones below it and hell to the ones above it; were there any Limits below the Nightmare save Absolute Death, the Nightmare would seem like heaven to them.
Castlevania: Order of Ecclesia features the Order of Ecclesia, whose agenda is revealed to be bringing about the reign on earth of Dracula. The protagonist, upon learning this, opposes the Order. Granted, it may have been the delusion or mind-controlled madness of one man, since at its peak the Order seems to have exactly three members.
If the Church of the Broken God of the SCP Foundation universe ever manages to reunite all the pieces of their "god", the result will most likely be everything on Earth (including the Earth itself) turning into clockwork.
Heaven for Viking men was an endless cycle of fighting battles, followed by drinking mead taken from the udder of a magical goat that heals all wounds. After a night of feasting, the men would battle all day once again. It was expected that all Vikings should think that constant battle and feasting is just awesome.
There's a certain amount of both Fridge Brilliance and Values Resonance when you realise this would be an awful lot like getting together with your buddies to play Team Deathmatch video games and sink a few bevvies between games. For eternity.