The stage most likely takes place deep in an underground cave that is inhabited by giant serpent Karnath.
Stage 6 has four sections that contain different-colored backgrounds as well as spikes and floors. In the first section, you jump on the snake and walk on the serpent to go to the next part. If you fall off, you do not die. Instead, you will have to wait for the snake to go back to where it started.
The second section has gray floors and a brighter background with different tiles. There are also spikes this time, meaning jumping will have to be with great timing. The third section has more modifications: there are more spikes and no floor. The spikes are made more difficult to get across, jumping will need to be perfectly accurate.
The final section, section four, has a floors that you can jump on you will still need some practice on this part. There is an occasion in this part of the stage where your hop off the snake will need to be high enough while being accurate. If the task is done right, you will land on the snake you have been riding on. You will soon pass the stage.
There is a warp zone in Stage 6. To get to it, make it through the first section of the cave and reach the next one. Then, as you climb up the snake again, dash diagonally across the all the spikes until you reach safe ground and run to the warp. If you get to the warp in time, you will be warped to Stage 8.