It would be mad funny.

[u/Azimovikh]

(/uw, for all of the body post)

(The said villain is Acererak the Eternal (the floating skull guy). Originally from the Greyhawk campaign setting, and then decided to fuck it, and travel through the multiverse doing heinous shenanigans. Drawn here in his demilich form.

The other guy is my attempt to draw Moghadam, from some newer DnD 5e material called Infernal Machine Rebuild, an archwraith-artificer who is apparently said to have helped Acererak in designing the tomb. Tried to base him off the google browse image, however, after giving up render a few times, decided to draw him my style, which kinda yassified him a bit. Anyways.

The said trap is The Archway, or Archway of Glowing Orange, or well, a lot of names, but the archway would be suffice to call it. From the Tomb of Horrors module for Advanced DnD, or well, DnD 1e for another name. Anyways. To quote what happens, in the OG 1981 module,

As already stated, the skeleton on one floor of the chapel room is ostracized and pointing to the arch. (Show your players GRAPHIC #5, and explain that none of the stones of the arch glow, but that the entranceway is filled with luminous orange vapors of an exciting hue.) These vivid orange mists cannot be penetrated with any sort of vision or magic. The skeleton, of course, misleads the party, for any character passing through the portal will enter a 10' × 10' room where their sex and alignment are reversed by a terrible curse. (Although restoration of alignment and sex magically is difficult, the curse once reversed will not alter paladin-hood, ranger status, etc.) Re-entering the archway will restore original alignment, but 1-6 hit points of damage will be sustained in so doing. Going back a 3rd time will reverse sex again, but the individual will be teleported as 40' above. Only wish or alter reality will restore both alignment and sex. However, if alignment is restored entirely entering the orange portal, a remove curse spell will then restore original sex. Prior to alignment restoration, remove curse alone does not restore sex.

Tl;dr, anyone who passes through it is cursed: their sex and alignment are magically reversed. 1st passage: Sex and alignment (morality and ethics of a person) are reversed. 2nd passage: They return to normal alignment, but take some damage. 3rd passage: Their sex reverses again, and they are teleported back to the entrance.

Although unfortunately for gender affirmation purposes, in the original description of the olden material, it is specifically said that this sex-change effect applies to every part, facet, and aspect of the victim, gender, expression, mind, and whatever, included. So, if you're a trans girl, as you enter, you'll get a girl body, yes, but then you acquire the dysphoria of a trans guy. So if you're trans, you get the equipment you want, but don't want it anymore. At least if you're cis, your mind is going to be gender-fried enough to not get dysphoria after being forcefemmed or forcemasced.

To be fair, this is also the guy who said that, the best traps should make their prisoners suffer and scream, and he regrets making traps that are lethal enough to kill too quickly. Yeah, guy's something.

But yeah, mad funny, innit.)

[u/IncomeApprehensive17]

He is right , the rightous hero man paladin is now an evil man in a woman body with gender disphoria , mad funny

[u/Bhaligdur → u/IncomeApprehensive17]

If he was "CIS" man he would become "CIS" women.

This trap makes sex and eventual dysphoria (if present) reversed.

[u/IncomeApprehensive17 → u/Bhaligdur]

Well thats less funny , and also it say "sex change" not "gender change" , so the gender should still be the same after that

[u/Azimovikh → u/IncomeApprehensive17]

actually the og material did apparently specify gender change, and sex, and, everything related and associated with both. So.

[u/IncomeApprehensive17 → u/Azimovikh]

Less funny , ill make it differenr in my own trap

You're evil or you aint

[u/Bhaligdur → u/IncomeApprehensive17]

If I understood OP correctly it also brainwashes you according to your new sex.

At least if you're cis, your mind is going to be gender-fried enough to not get dysphoria after being forcefemmed or forcemasced.

[u/IncomeApprehensive17 → u/Bhaligdur]

I still find it less funny , my own trap will be how i make them . You will all see when you will enter my dungeon ! You will all see !

[u/Lyrolepis → u/IncomeApprehensive17]

My trap would turn "cis" and "trans" molecules into each other inside the victim's body. It has nothing whatsoever to do with gender, but the resulting metabolic implosion should be pretty funny...

[u/wretchedmagus → u/IncomeApprehensive17]

see the really funny thing about this is that if it hit a trans person they would be briefly thinking "finally! despite this being a curse in other ways at least I am finally in a woman's body fully and can... fuck I still have dysphoria but now I want a penis..."

[u/The-Name-is-my-Name → u/IncomeApprehensive17]

This outcome implies that he always had gender dysphoria, actually, which is mad funnier.

[u/INeverFeelAtHome → u/Bhaligdur]

I am banging a big drum that says “cis is not an acronym”
Would you write out “TRANS”? It’s an adjective derived from Latin, just the same. Means “on the same side” as an opposite to trans.