Blob Monster in Cave/ Mine

[Isabel]

Looking for a book I read as a kid in approx 2008, it was about a guy who finds a blob like monster. Pretty sure it was in a cave or mining area, may have been in Arizona ir New Mexico, and there was some sort of gift shop. I feel like it was really an adult book but I read it in elementary school. Cant find it anywhere, and it's not the goosebumps book. Thank in advance

[Isabel]

title should say mine not mind

[Rainbowheart]

Does anything on these lists look familiar?

Novels Set in Arizona

Books Set in New Mexico