Some obscure horror movie about some red monster in a cave

[Hamzat]

There is little hope, but I'm going to try anyway. I did not see this movie (or perhaps an episode of some TV show) myself, but I want to help a girl who complains that she has been searching for this flick for half her life in vain.
According to the plot, a small group of students (or just young people) goes somewhere into the jungle with some witch. The witch is a black-haired young woman. Along the way, one of the girls fell into a swamp or quagmire and everyone helped to pull her out of there.
There was some kind of cave where they repeatedly encounter all sorts of crap. A spider crawled into one girl's mouth after she dropped her glasses, and something fell on a guy's head and he lost consciousness. Another girl came across a red bathtub (kind of) , and from this bathtub a humanoid monster began to rise, all red, bald, and with empty eye sockets.
Then that witch "treated" in a tent that guy on whose head something fell, and meanwhile this guy himself was growing similar to that creature from the bathtub in the cave, red and with empty eye sockets.
She doesn't remember anything else.
The movie was probably released between 2000-2010.