Need a side character to give information for a chapter -> okay here's a lady who looks like a fearful rabbit but is incredibly, surprisingly strong physically, has filled out her apartment with tons of clutter from a long life full of memories she doesn't want to get rid of, and cares very deeply for her husband, his dog, and still cares but more from a distance for both Sam and Mavis, that should be enough characterization -> hahaha what if the reason she cares so much about how Mavis is doing when everyone else is creeped out by Mae is because she's also a vampire and is very aware of how bad Mae is taking care of herself -> haha that'd be silly -> ... -> wait
Her being a vampire as well fits way too comfortably with her hoard of momentos and unusual strength and I'm actually pretty attached to this idea for her now. -> changes her last name to one that includes wolves in the meaning, as a little nod to Dracula and his command over wolves that no one besides me will catch -> beginning to feel head swimming with ideas of her being involved in the story for more than what I initially needed from her
Lady has a husband, what's he like? -> don't really need him in the scene, I'll just give him some characterization by having the dog belong to him, he usually likes to get small dogs, and he's currently away as a (throws dart at board) airline pilot -> his wife is now a vampire -> does he know? what am I saying they're married of course he knows. He helps her hide it. -> but wait her last name comes from him how does this work in my silly Dracula reference -> he took her last name instead (nice implication of the role reversal and a show of either how much he wants to be considered a part of her family or issues with his own family name that range from mild to severe, could work with that) -> or it is his last name and just a funny coincidence (=/ not fond) -> or haha wouldn't it be funny if it's his last name and he just so happens to be a werewolf -> ...
... he's very attached to his dog -> the little ones were like pups to him -> nod to Dracula with power over wolves -> ...
Just a little peak into how my brain has worked for these two. I don't think I'll really stick to the werewolf development in my actual writing, as the whole vampire and werewolf in a romantic relationship seems to be even more of a cliche now than them being natural enemies. But it is silly and compelling in a way.