Here’s a fun idea: a vampire gal who drinks curvy women’s blood not for food, but to assimilate their DNA so she can give herself the same assets. She could either accumulate the measurements of multiple people at once (though that would mean that sooner or later she’d become too big to move and hence bite anyone else), or she could be more like a shapeshifter, able to cycle through the various booty and boob sizes and other physical qualities she’s sampled. I’d personally rather see her leave her victims alive and with their figures intact, though maybe she gives them the same power she has.