Spray-shaped drawings in an inner gallery of the Chauvet cave may depict a volcanic eruption. Left: general view; right: traced detail, with an overlaid charcoal painting of a giant deer species removed (lower right). D. Genty (left)/V. Feruglio/D. Baffier (right)/CC BY 4.0
That’s no volcano eruption picture.
What it is, is a pic of a camel that was drinking a glass of milk when the other critter (the squiggle on the left of the pic) told a joke that was so funny it made the camel expel the drink from its nose.