That's just an interpretation of the some of the paintings.
Interpretations are a very subjective assessment and change over time.
For instance, the same paintings are interpreted as representations of extra terrestrial creatures.
Not need to use a supernatural explanation for something that can be explained by normal events.
https://www.darwinandwallace.com/products/fetal-human-skelet...
(Even if a mushroom or proof of its usage was found nearby. Rock art specialists have found that dating rock art by the surrounding context is not the correct technique. As newer methodology has found that the surrounding context can lead to dating thousands of years off. It’s best to date the art directly)