Well, this is VERY specific, but I've been getting way into making a "bad end" for the Skullgirls game with giantesses and writing a collection of short stories about it.
If you don't know the story of Skullgirls it involves a cursed artifact called the Skull Heart appearing once every seven years and trying to trick the women of Earth into making some kind of wish on it. It ALWAYS corrupts the woman's wish and turns them into a Skullgirl, an undead lich queen like being who commands armies of the dead. She then goes crazy and attempts to destroy the world.
Usually there's only one Skullgirl at a time but in the story I'm writing, the creators of the Skull Heart obtain the powers of a mysterious giant tree from another world that allows them to ramp their efforts up to 11 and create many new ultra-powerful "Giga Skull Hearts" that lets them turn pretty much the entire main cast (save for a couple of them) into giantess Skullgirls all at once, who then proceed to annihilate the human race.
I hate Skullgirls and the people who made it but I do sort of like the world and characters, and I've become slightly obsessed with this story. I hope it doesn't detract me from making my other size projects. Yes, I am the GigaMaidens fag and I am still working on it, and this is a crossover story between it and SG. I've been working on it since before SG has been out and will continue to do so.