SOLVED. 70's Sci-fi, Cave, And something called a Scooch? [s]

[Skot]

Looking for a book for a friend of mine, They believe it was written in the 70's but can not remember much about it. It was described to be as; "A guy finds a weird cave. Decides to explore it. Finds out it's deceptively deep. Gets trapped in it so decided to see where it goes. The deeper he goes the weirder it gets. Finds a chasm with monsters. Gets followed by a little "thing"/monster that may or may not be a hallucination. I think he called the "thing" something like a 'skooch' or 'scooch'."
I probed for more information but that is all should could remember up to this point. I will update if/when more information becomes available. Thank you.

[Andria]

Skook?

[Skot]

Andria wrote: "Skook?"

Nailed it in one. Thank you.

[Rosa]

How did you find that one, Andria?

[Andria]

Rosa, I don’t recall what resource I was searching (maybe worldcat?) but I used pretty simple keywords like cave and monster, limited to adult fiction w/ 1960-1980 pub date, and the title jumped out from the list of results.

Happy to help!!