Fear fish (scientific name: Dunkleosteus) is a large prehistoric fish of the order Scutellopterus and Neck-saving fish. Its body length can reach 10 meters. Its head and trunk are wrapped by bone carapace, and its front jaw has scissor-like bone plate teeth. Its bite force is estimated to reach 6000 cattle. Fossils show that its upper and lower jaws can move freely, and its mouth is more than 1 meter wide, which is the top predator of the late Devonian period. China's Sichuan Jiangyou has been found about 1 meters long phobic fish fossils. The phobic fish lived in the late Devonian period from 0.36 billion to 0.4 billion years ago, distributed in Morocco, Poland, the United States and other places.

Deng's fish is a genus of fish in the family Scaridae, also known as the shell fish. It is the largest known shield skin fish, with a body length of up to 11 meters. The body shape is spindle shaped, similar to that of a shark; The head and neck are covered with thick and hard shells; The skin on the back is dark in color; The abdomen is silver in color. Living in Devonian ancient organisms, inhabiting shallower waters. Being able to prey on any creature in the ocean at that time, he was likely the first king of beasts on Earth, more than 100 million years before the birth of the first dinosaur on land. The largest predator in the Devonian ocean and the largest carnivorous fish that has ever appeared on Earth is known as the Tyrannosaurus rex in the ocean.