It almost looks like a still from a forgotten B-movie, but it’s actually an illustration from the first Czech edition of Jules Verne’s 20,000 Leagues Under The Sea by Zdeněk Burian, 1937.
Burian is a favorite but I didn’t know he did this kind of work. I mostly know his paleontologic reconstructions.
Cthulhu rises?
Burian focused on artistic paleontologic reconstructions of ancient animals and beasts, in cooperation with scintists. Mostly ilustrations, scientific or popular. Here is a big one, oil on canvas 170*117cm.
I don’t remember this one but I like it. The pit trap is likely fantasy but it is a cool image.