Special thanks to my dear friend and wonderful dm @mushroomflowercrown for the collaboration on making this nasty boy!
(Art is The Plague Doctor by Colin C Throm, couldn’t quite fit the credits in on the page)
Worth noting that the Parasite feature is susceptible to the Bag of Rats issue, which is a little ironice what with the whole Black Plague Doctor theme.
If you’re worried about that, I would stipulate that you can’t gain more healing than damaging the creature actually does. Therefore, killing a 1hp rat (or any other small creature) gives half a hit point which per dnd rules is rounded down, and heals nothing
This technically doesn’t stop someone from bashing an elk to death to heal themself, but as a dm I think it’d be fairly easy to not make tanky easy prey accessible. Also if your player does that they’re kind of a dick. Feel free to play around with the stipulations of the ability, I never really thought about it being used that way.