Entwife porn is definitely a niche genre.
Obscure, kinky LOTR caption takes the prize. @Lumpy, it’s yours.
On our new rifles, if you try to rest the end of the stock on your arm while shooting, you can’t do it. Rest it against your your buddy’s crotch instead.
The LGM (Little Green Men) find Andy’s stash of toy guns… or are they?
The Army recruitment outreach to men with small penises was an outstanding success.
“Alright, the enemy shrink-ray worked on you too, but YOU ARE STILL MARINES! I will teach you to fight as you are, and kick those aliens’ asses! DO YOU HEAR ME?”
The Overcompensating Brigade
So many great answers but since there can be only one…
AI creation.
Who’s the weirdo with the guitar?
It was a tough crowd, but Mary Sue wowed them.
Ensign Moira was advertised as performing for a “monster” crowd.
The TOS episode titled “Scheherazade” was a lot more horrifying than this illustration lets on.
Linda Rondstadt was all set to do the Halloween Star Trek episode, but walked off when Gene Roddenberry kept insisting they make her uniform shorter and shorter.
Star Trek struck.
With her regular banshees unavailable, Siouxsie was forced to improvise.
“Okay, all together everyone! 
KUM-BAY-YA, my lord, KUM-BAY-YA..”
Lots of good entries, but Lumpy wins for correctly identifying the character trope. WTG 
The character was actually a cosplaying fan at a sci-fi con. It was her guitar case that was supposed to be festooned with fannish stickers, and she’d just led a filk circle in singing Tom Smith’s “I Had a Shoggoth” but the image generator took all the monsters in the song literally.
Thanks @Ponderoid Now for something for folks to ponder:
