While very short it inspired my writing for years to come and remained a fond memory in my mind,  even as I forgot the remainder of the book's story.  The protagonists of course escape the snake's stomach,  but in a wonderful aversion to the usual outcomes here  they do it without harming it, the snake spitting them out on the surface then burrowed back underground irritated.

So, my idea here was some hours after the snake had spit them up and returned below ground. Two individuals had approached the area to investigate the commotion.  The snake detects them approaching and bursts up from underground and swallows them along with a large mouthful of the dirt they were standing on,  then burrows back underground with its new meal  -  and this time the snake would be keeping it.  No escaping the stomach this time,  its prey will digest like food is meant to!