One thing I've always loved about vampire stories is that there are no hard rules. Vampires can be whatever the author wants them to be as long as they're internally consistent within the story. This makes them extremely versatile monsters that can be constantly re-invented and none of them are "wrong".
For example, sometimes all it takes to turn into a vampire is to be bitten by one. And sometimes you have to drink the vampire's blood to turn. Or, sometimes a vampire can just drain your energy without transferring any blood at all.
Of course, the rules can also get a bit ridiculous. Maybe the vampire is required to obsessively count grains of rice first. Or maybe they're required to hop around with their arms out (the chinese Jiangshi). Maybe they can turn into a wolf, a bat, or... fog.
So what's the most ridiculous rule or type of vampire you've come across?
(For the image on this post I wanted the most ridiculous picture of a Jiangshi I could find. I went with a shot from Robo Vampire which has a really fun RiffTrax. The only other Jiangshi I'm aware of is in the NES game Phantom Fighter... because I've never watched any of the Mr. Vampire movies)
It would be a poor parasite which always killed it's host (and parasitic organisms which always lead to the organisms death while said parasites exponentially reproduce in host body ia different imo).
Vampire bats for one don't really affect the cows and whatnot they suck on afaik. Although that reminds me they have to keep constantly pissing because blood is relatively nutrition poor and they'd just become bags of liquid, so they constantly piss while drinking.
Now imagined Dracula with his schlong in one hand every time he feeds