Have you seen a huge rock (or even whole mountain) looks like a creature?
Those rocks were huge fossils created by mud deposit over alive creatures such as dinosaurs because of mega flood. Or they were created by hot volcanic ash covered those huge alive creatures and made them fossils in quite short time just like stoned people in Pompeii.
Stoned bodies in Pompeii
The following video explains why dinosaurs extinct. The violent Earth movements finished those dinosaurs and made many fossils and rocks (and even mountains).