I thought I'd toss out an RP based on Frankenstein's Monster and the Bride of Frankenstein. Details negotiable but here's a few possible ideas.
Set in Modern Times -
A young woman goes to a costume Halloween party as a sexy Bride of Frankenstein, as in the female version of the Creature invented from the movies of the 30's. The costume is a hit, and she ends up having sex with a man who she thinks had a similiar idea with a handsome Frankenstein's Monster costume.
Except afterwords she finds out that her paramour of that night wasn't just a man in a Frankenstein's Monster costume but the Real Frankenstein's Monster...
In 1818, Dr. Victor Frankenstein using his genius created a living being. A man, born not from a woman's womb but from the corpses of the dead and a bolt of lightning. The creature did not please him, and instead of celebrating his victory over Death he tried to kill his creation. The creature survived, and their fueled began.
In 1825, their fued having already cost him dearly, Dr. Frankenstein offers a deal with his Creature. His experiments having continued, the Doctor now thinks he can create something better. In exchange for peace, Dr. Frankenstein has proposed to create a companion for the Creature, a female version of the Monster that will benefit from several more years of previous experiments known simply as 'The Bride'.
But is the Bride truly Dr. Frankenstein's peace offering to his "son" - or the instrument of his Revenge?
It's an old story, hidden from the world. In 1818, Dr. Frankenstein created the Monster. In 1825, Victor tried again with a female version of the creature known as The Bride. The Doctor always did view the Monster as a failure and the Bride as his greatest success. He did too good of a job on the Bride, in the Doctor's humble opinion. He didn't think she'd be just as Willful as the Monster turned out to be.
One thing that none of them expected was the lifespans of the Creatures. Years would become Decades, Decades became almost 200 years and both Monster and Bride seemingly have not aged. Are they truly immortal? How long are they going to walk the Earth?
Their paths frequently part and reunite, and tonight they have once again.