Quatch seems to go with legendary monsters. The other legendary monster which I think predates the batsquatch is the sasquatch monster.

The following dictionary definitions seem to be helpful, and the synonym listed in the second definition - abstruse, meaning hidden, or concealed or hard to understand or mysterious is relevant, as is the adjectival use as languid meaning slow moving, or slow and awkward as it seems to be used with some of these legendary monsters.

The word was used by by Shakespeare in All's Well That Ends Well to be funny (and in that case possibly meaning squashed or flat), and that it continues to be used humuorosly as best as I can tell.

HERE’S THE SHAKESPEARE from All’s well that ends well:

CLOWN Truly, madam, if God have lent a man any manners, he may easily put it off at court. He that cannot make a leg, put off’s cap, kiss his hand, and say nothing, has neither leg, hands, lip, nor cap; and indeed such a fellow, to say precisely, were not for the court; but for me, I have an answer will serve all men.
COUNTESS Marry, that’s a bountiful answer that fits all questions.
CLOWN It is like a barber’s chair, that fits all buttocks-the pin buttock, the quatch buttock, the brawn buttock, or any buttock.
COUNTESS Will your answer serve fit to all questions?
CLOWN As fit as ten groats is for the hand of an attorney, as your French crown for your taffety punk, as Tib’s rush for Tom’s forefinger, as a pancake for Shrove Tuesday, a morris for Mayday, as the nail to his hole, the cuckold to his horn, as a scolding quean to a wrangling knave, as the nun’s lip to the friar’s mouth; nay, as the pudding to his skin.


quatch A shortening of the word "sasquatch". A quatch is person that exhibits sasquatch-like characteristics. (ie. walks slow, has long arms, or may also make totally ignorant statements
Mate 1: Man, did you see Issac run into the door?
Mate 2: Yeh, what a quatch.

http://www.urbandictionary.com/define.php?term=quatch

Definition: Quatch

Adjective 1. Squat; flat.[Websters]

Adverb Form
(quatchly) 1. Virtually never used adverbial inflection of the rarely used adjective squatch.
Source: Webster's Revised Unabridged Dictionary (1913), compiled from various sources, under license.

Date "Quatch" was first used in popular English literature: sometime before 1602.

Synonyms: quatch
Noun: abstruse, jejune.
Adjective: flat, squat, heavy, low, poor, stodgy, sturdy.
Consider also: depressed, depressing, despondent, dingy, dismal, dreary, dumb, feeble, flabby, flaccid, gaunt, gloomy, gruff, harsh, languid, languorous, lax, listless.
Other splay.

http://www.websters-online-dictionary.org/definitions/Quatch...