The wall walking is a very useful skill if you are trying to reach high places.
The creature can walk on sticky surfaces no matter if they are grounds, walls or ceilings.
But it has some limitations, is easy to fall down if you do strange things such as change your form, use your horns, jump… if you want to stay stuck, I beg you: just walk! (you may find an uncomfortable landing on spikes if you don’t follow this advice).
Anyway… you will only be able to stick on these strange green mucus… but who or what has spread them along the cave? It’s difficult to know, but maybe you can find the answer inside the cave…