"The Mannikin"

by Robert Bloch

originally published Weird Tales May 1937

Our narrator is yet another head case under professional care who has a wild tale to tell us about how he got driven nutso.

It seems he's a college professor and as big fan of fishing, and went on a little trip to a lake resort near a village called Bridgetown.   There he runs into a former student - Simon Maglore - who was brilliant and rich, but also a weirdo who studied the occult and drew pictures and made sculptures of demons and witches - oh and he's a hunchback.  Needless to say, brilliant and rich he mighta been but BMOC he weren't.  Anyway, Maglore seems to be in poor health - his hump's doubled in size!  And says he's writing a monograph about (surprise!) witches.

Taking pity on poor old Simon, our narrator noses around town, discovering the Maglore family is disliked and always has been - for the usual reasons - and Simon especially so - for the obvious reasons.  He decides to drop by and suggest that Simon Lay off his witchcrafty studies for awhile.  While visiting - he thinks he sees the hump move.

Our narrator visits the local doc the next day, repeating what he's seen and Simon's crazy-ass talk about witches and familiars the night before, and the doc readily concludes that Simon should be locked up for his own good (gotta love 30's pulp fiction psychiatric practices!).  They hotfoot it over to Simon's pad only to find him dead in a pool of blood.  Which is bad.  Even worse is that he's shirtless, and that was no hump on his back - no - it's a parasitic twin!  Which has bitten old Simon to death (and therefore killed itself - stupid parasitic twin!)

Notes left behind by Simon (this is the best part!) explain that the twin had been growing since his college days and needed human blood to survive - which Simon had been providing, thus solving several local unsolved murders.  But it kept growing, and wanting more more more, and taking over poor Simon's mind.  Gak!

This is a nothing-special story, but it is highlighted by the truly hilarious excerpts from Simon's diary, in which he argues with the twin, even to the point of telling it "No! Stop! Get your hands --" thus committing the Greatest of All Lovecraftian Sins, the old "write down your dying words even as a gloop monster is devouring you bit".  

Now Bloch was known in later years for the black humor he injected into many of his tales, so its possible he meant this one to be tongue-in-cheek.  Possible.  And as much as I like Bloch and want to give him the benefit of the doubt, this one's hard to take seriously or find funny.