Used to be obsessed with paleontology as a kid.
But anyways, a species that shook me to the core when I first read up on it is the Daeodon.
''These hoofed mammals (artiodactyls) have been nicknamed “terminator pigs”, a reference to the fact that these brutish animals come from the same branch of the hoofed mammals, the ungulates, as pigs, however, recent research suggests that the eight or nine genera that make up the Entelodontidae family are probably more closely related to hippos and whales. However, a Daeodon model (member of the Entelodontidae), has been produced.''
''Fossilised footprints and bone bed discoveries suggest that these omnivores lived in small family groups and that during the Oligocene and the early part of the Miocene epoch, they became adapted to open, savannah-like habitats. The long legs would have helped them cover large territories as well as helping them to adapt to a pursuit hunting habit. The strong neck muscles helped support a skull that in some species was over a metre long. The thickly enamelled teeth and those large fangs located on both the upper and lower jaws would have given this prehistoric mammal a devastating bite.''
https://blog.everythingdinosaur.com/blog/_archives/2015/09/03/the-mighty-daeodon.html
I am shocked that a creature like this used to roam the lands, and grateful that they've been wiped off the face of the earth lol.