(See also http://bxblackrazor.blogspot.com/2010/09/halfling-love.html from 10 years ago, demonstrating giant killer credentials: I am so late and I cannot keep up)
Because of my own historical anti-Tolkien prejudice (for better or worse, I conjure Fafhrd and Grey Mouser when I think of the basic fantasy adventure set-up) and cleric fetish, I didn't have much time for halflings in any edition or setting. Even the Athasian 'cannibal halflings' weren't as interesting as that sounded (opinion, not fact) when Dark Sun was trailed.
Re-reading old gaming materials, I was struck by a very different halfling to the image I had from fictions and illustrations.
Ye olde halfling (and 'mine' isn't the oldest) already plays well as a monster, if you wipe off the 'hail fellow well met a tankard for my friend and a little something for my pipe'. Forget Tucker's Kobolds: halflings are the Goblins of the Labyrinth, scuttling round Sarah's house.
(Incidentally, these abilities don't appear in the monster section entry)
These are ambush predators as much as hide-behinds; these are borderline supernatural powers.
What are the natural surroundings of halflings in your setting?
And the locked pantry. The dark root cellars winding off into the depths of the hill. Feeding you up, insisting you stay. You lay down for a nap in one of the guest bedrooms.
More Parents (1989), maybe, than The Hills Have Eyes (any of them).
Phalse, from Azure Bonds (1988 Forgotten Realms novel), wasn't technically a halfling, but reading his sleep assault on Olive Ruskettle put another shiversome sheen on the hairy-footed ones. I would have been about 12/13, impressionable, and I've never really been able to shake the perception of an inbuilt capacity for creepiness.
Finally, there's a good reason I used the halfling experience table and saving throws as the basis for the Old School Shoggoth Race-as-Class.
IIRC, in both D&D (Mystara? Blackmoor?) and WFRP there is or was some lore that halflings were created, built for purpose; I think, by the Old Slann, to resist the warping power of Chaos, and by some Immortal-or-other to resist (amongst other things) radiation.
Even if my recollection is faulty, it puts me very much in mind of HPL's Old Ones/Elder Things/Primordial Ones, and their highly resilient manufactured species of slave-machines...
...something I'll return to in a later post, once I've compiled the notes.