Not a gender-bender, but a reality-bender! Lol...

I'm looking for a manga that questions the nature of reality, and makes the protagonist(s) doubt whether what they're seeing/experiencing is real. So, obviously a psychological manga to some extent... A manga that makes you feel sort of like you're inside an optical illusion, in the sense that there are different ways of perceiving reality, and you can't ever be sure that any one way is entirely correct.

After School Nightmare is the consummate example of this (that I've found) - reality is so totally messed up, and it's hard to separate what is real from what is not. And this is despite the fact that the characters (mostly) aren't crazy...

Homunculus questions the nature of reality, too, as does Paranoia Star.

I'm also dying to read a manga like the movie Waking Life, which is basically a philosophical questioning of the nature of reality... Don't know if such a manga exists, but I'd love it if someone could recommend something even vaguely like it!

Other scenarios that might apply:

The protagonist experiences "reality jetlag" after returning to the so-called real world after time spent in VR;

A Matrix-like manga in which everything we think of as real is actually NOT real;

The protagonist is just plain crazy and therefore has hallucinations that aren't real, but seem like they are;

The protagonist has really vivid dreams/flashbacks that "bleed" into daytime life and cause disruptions;

There is some sort of mass hysteria/delusion affecting the general populace, and the protagonist is the only one who sees (or thinks s/he sees) the truth;

The protagonist has spiritual/out-of-body experiences that conflict with normal notions of reality;

There is another world underneath/running parallel to our own, that we just don't know about but is actually just as real (e.g. Narnia or Torchwood).

... Lol, you get the idea. These are just some possible scenarios for reality-bending manga.

Any recommendations? Absolutely any genre is okay, except hentai or ecchi. Shoot! 🙂

Goodnight Punpun

and maybe Gogo Monster (not sure since I haven't read it yet).

[url=http:////www.mangaupdates.com/showtopic.php?tid=42718][img]http://i366.photobucket.com/albums/oo105/CatzCradle64/Avis-Sigs/FunghiPower_zps2a00ba56copy_zpsfc03990e.png[/img][/url]

Milk Closet - so very, very much.
Swweeet - They just finished scanlating it today - I need to reread it to work out what the hell happened.
.... also, The Music of Marie

Bait and switch ending! Ragh!

Princess Tutu - watch the anime, though
Kaiba - again, anime, but it's amazing
Monster

I didn't finish this one and you've probably read this one already but I'll still suggest this one since what I remember from it does kinda fit: Mekakushi no Kuni

Also, if you want (a) crazy - I mean totally insane - character(s), you could try Freesia - sometimes you wont know if what is happening is real or some of the characters delusions.

Believers...

Amatsuki - art is good, but the story is a little bit slow at times.
Heart no Kuni no Alice - might fit, since it's like a remake of Alice in Wonderland.
Camelot Garden - this is the closest thing to your request. However, it's only a oneshot. But I highly recommend reading this.
MISSING - it doesn't deal with reality, per se, but I would recommend reading this and the novels.

Would you like to join the Axis Order?

I recommend Drifters

Plot:
There's a man in a room that takes warriors away from our world and sends them to another world there they are refered to as Drifters, someone else takes warriors who hate's our world and sends them to the other world.

The kingdom in the other world wants to unify all the drifters and have them lead there armies against the Black King (a King of Death) and he commands the other warriors along with his armies

However our Main Lead have not intresst in Serving this kingdom.

The warriors that appears in this story are mostly famous once from diffrent eras of our world.

It is a bit messy in the begining but I myself really liked it

If you want to succeed
Then you don't need Good Luck
You need the ability to overcome Bad Luck

Happines and Light needs a source to exist
Hatred fuels itself and Darkness exist where there is no Light

[img]http://www.nodiatis.com/pub/7.jpg[/img]
† Lightmare †

I second Freesia and Believers, and I add Level E as well as some Boogiepop.

Sarcasm just doesn't work over the internet.

Ultra Heaven
Gogo Monster
Freesia
Tropical Citron
Me and the Devil Blues
Ressentiment
I am a Hero
Soil

[img]http://i53.tinypic.com/nq73ao.jpg[/img]

Quote from purple716

Is there any manga where the male lead has an illness known as stomach ulcers.Yaoi are fine top.

I totally second Camelot Garden, Ultra Heaven and I am a Hero.

Yumekui Kenbun and Domu fit to some extent.

Discommunication Seireihen

Plastic Girl (FURUYA Usamaru) and Garden (FURUYA Usamaru) - Actually, I think some of Furuya Usamaru's other manga might work as well, but I haven't read them.

Soil - Not so sure about this one, because I stopped reading it on the 2nd volume; but I get the feeling you might like it.

You could also try the Mindbreak and Hallucination categories.

Bump - This is such an interesting topic! Why are there so few posts? 😐

Slow Down sounds a lot like what you want.

Ilegenes

I am the master of my fate;
I am the captin of my soul.
William Ernest Henely

I rate manga with 5 being the average score.

[url]http://www.mangaupdates.com/series.html?id=6765[/url] Mirai Nikki, you may not find it exactly what you are looking for in the beginning, but after a while, the idea of a not real world starts to develop in a great extent. It is a good manga in my opinion, with not common characters, reactions and a story that you just don't know for sure what to expect in the beginning, but can't stop feeling that you do want to keep reading it although you don't really find any special "ingredients of your taste" but end up liking it. Maybe not what you are looking for, but does have a "reality bender" sort of thing

Another one is [url]http://www.mangaupdates.com/series.html?id=341[/url] XXX Holic, not some crazy character thinking about reality, but as you read it along with Tsubasa Reservoir Chronicles, you understand the idea of different dimensions (resulting in realities) that is discussed in this manga's story. Tsubasa and Holic are mangas that have a link between their stories, some answers for some matters are found in each manga.
However I highly recommend reading Holic, the manga itself is great and for a good reader there is no need to read Tsubasa. Therefore, back again to the reality bender matter, in Holic you will find some philosophic discussions in a bunch of matters, but the main subject goes around the dimensional and character growth, in the case Watanuki and his experiences with the supernatural, that later (trying my max not to spoil anything) relate to dimensions, therefore, realities.

Hope it helps, I bet that there are a bunch of others, i might as well look for some more because I also got interested in the topic, but right now I can't think of any others and I am in a little bit of a hurry, see ya ;D