The Triassic period was a time where evolution was just like "Fuck it." and created the weirdest variety of reptiles to have ever walked the earth. Among these reptiles was this bastard lovechild of a Komodo Dragon, a Predator, and a flamingo: Atopodentatus. At around 3 meters in length (10 ft), it was an average sized animal for the day 247 million years ago. It was a filter feeder, which is pretty disappointing considering it looks like it was a predator that was just shit out of Life's creative asshole after a bad trip on LSD.
Eugeneodontids are honestly so fucking cool. They have the trippiest jaw structures to have ever been put on a fish, ranging from actual shears, to knives, to this Pokemon looking fuck. Helicoprion was one of the largest predators swimming around in the late days of the Paleozoic era. It grew to an estimated 8 meters long (26 ft), and is thought to be related to today's chimeras and rat-tail fishes. It was a long lived species, surviving the greatest mass extinction event that wiped out 90% of life on earth some 250 million years ago.
But you don't care do you? You're thinking about the fact that someone out there strapped a fucking buzz saw to a fucking shark and said "YENNO WHAT WOULD BE COOL? A BUZZ SAW ON A FUCKING SHARK!"
"Two forms of teeth"
There is the assumption that Dimetrodon was a dinosaur, even though it lived some 40 million years before the first dinosaur even took its first steps. It actually was a synapsid, or better known as "mammal like reptiles" as they had characteristics of both mammals and reptiles ya dingus. Dimetrodon grew to around 4.6 meters (15 ft) and was one of the largest predators of its day.
Believe it or not, whales used to look like this bastard lovechild of a crocodile and an otter. Ambulocetus took advantage of the void that was left by the extinction of the great sea monsters that lived during the dinosaurs. It went into rivers and lakes and owned that shit. It hunted early horses and competed with crocodiles in its territory, even though it was only 3 meters in length (10 ft).
"Whale that walks on its teeth"
...literally I have no idea what the fuck evolution wanted to go with this fuckwad. It looks like a walrus mated with a flounder and grew lopsided tusks. But it's a whale. Yeah. We went from a badass croco-otter to this fuck. Actually, I know what this thing was used for. It was used for food. Yeah. This 2.1 meter long (6.9 ft) fuck was used to give Megalodon a light snack. That's why evolution made this thing.
Speaking of Megalodon, sharks have been in existence for about 400 million years. They've produced some of the most badass hunters in existence like Megalodon. However, sometimes during the early days of development, you get some bugs. Stethacanthus was probably one of those bugs. Living around 320 million years ago, this 2.3 ft fuck was a small little tyke with a weird anvil for a dorsal fin. What its doing there, we still don't know.
The family of animals known as the anomalocaridids are some of the strangest and weirdest creatures to have ever existed on our beautiful, amazing, ancient, and fucked up planet. They consisted of 3 meter long (10 ft) filter feeders, or some of the earth's first super predators. They developed eyes that were much more advanced than their prey. Just imagine a giant swimming cockroach. That's what an anomalocaridid is.
Dinosaurs came in all shapes and sizes from the mighty Mapusaurus to the miniscule Mei. They also tried to be the weirdest family of animals to have ever fucking existed. Therizinosaurus was a theropod dinosaur, meaning that it was related to carnivores like Tyrannosaurus rex. However, it was a herbivore. It also had 1 meter long (3 ft) scythe like claws that would make Wolverine jealous. Fucking genius, evolution. Fucking genius.
"Four roofed tusks"
If you've seen LoTR, then you've seen the Oliphaunts. And if you've seen the Oliphaunts, you've basically seen Stegotetrabelodon. Stegotetrabelodon was a primitive elephant, stood about 4 meters tall (13 ft), and is much more fucking badass than elephants that we have today. Look at it. FOUR TUSKS. FOUR. FUCKEN. TUSKS. Stegotetrabelodon is also important because their fossils depict the first ever evidence of prehistoric elephant herding behavior some 6-8 million years ago.
A North American mammal with its own built in slingshot. Basically sums up Synthetoceras. It was around 2 meters in length (6 ft), and was common throughout the plains of North America up until just around 8 million years ago when the weather started to set in and we got Ray Romano voicing mammoths.