Oh wow, if you guys want hostile, check out Marina Warner's book No Go The Bogeyman: Scaring, Lulling and Making Mock, which won the Briggs Folklore Award. (Azizi, did you ever come across this?) Go to Amazon - using the Mudcat link on the introductory page of course - and browse the reviews, which pretty much say everything I could.

She cites the Icelandic lullaby The Child In The Sheepfold wherein the baby sings to its mother, rather than the other way around, and you discover that the baby has been deliberately left outside in the cold to die. While the mother is milking a ewe in the sheepfold she complains to another dairymaid of having no fine clothes to wear to go to a dancing and storytelling festival (vikivaki). Then they hear a tiny voice coming from under the wall, who soothes the mother thus:

Mother mine, don't weep
As you milk the sheep, sheep
I can lend my rags to you
So you'll go a-dancing too
You'll go a-dancing too

I wonder if Skarpi ever heard this, and what his take on it is.

There's also this, from Tommy Thumb's Pretty Song Book of 1744, which is demeaning rather than hostile, though I can imagine it being sung affectionately:

Piss-a-Bed
Piss-a-Bed
Barley Butt
Your Bum is so heavy
You can't get up

But it still gets left out of the modern anthologies. Interestingly, I have a photocopy of an unpublished 1799 handwritten manuscript of Kentish dancing-master's fiddle tunes, and one of them is called Barley Butt, though it's a slide-like jig (there are a lot of Irish tunes in that collection) and not a gentle lulling melody. I always wondered about that title - sounds like the sort of insult we used to hurl at each other in high school. Not exactly sure what a barley-butt IS, though my imagination quite happily supplies all sorts of unsavoury images.

Warner remarks that the early printed tradition includes many harsh or bawdy lyrics, worn smooth over time. And yes, Rock-A-Bye-Baby's in there, from Gammer [Granny] Gurton's Garland, 1783 and no doubt other sources. Remember Maggie's terrified reaction when Marge sang it to her in a Simpsons episode?