Children's Sci-fi Action book I read around 2010-2013
Style/Theme: Sci-fi, Fantasy, action
The premise:
2 Teenage boys (I can't remember their names) wander into a cave, and end up being transported or taken to a different world.
They then start exploring the new area, which I could best remember is described as a forest or jungle like scenery, and end up coming across a Large, Bipedal, roundish robot/machine (imagine like Penny Parker's Spiderbot from Spider-verse).
It then starts coming after them and hunting them, with 2 other identical robots, and the teenagers have to outsmart them to fight back.
Extra Details:
The book itself had no images, but the cover had the 2 teenagers and an image of the robot described in the scenery.
The book also had an audio CD pouch inside the front cover, and its tailored towards a low reading level as I read it in a school classroom around 4th grade-ish.
The absolute most I could get out of google for it was "The Cave" and "The Planet" by J.H. Brennan as its a multi-part series I believe, however no books show up whenever I try to find them using those names or descriptions.
If those books do not exist on the internet and cannot be found, I would still enjoy hearing about if other people have read such book and remember it aswell.