The Ordovician Organisms (South Park)

The Ordovician Organisms is an upcoming South Park episode which features the paleozoic ancestors of the modern day characters.

Premise
475 million years before the events of Cartman Gets an Anal Probe, the single-celled organism/amoeba ancestors of Cartman, Stan, Kyle, and Kenny are living beneath the Pacific Ocean during the Ordovician era. In the beginning of the episode, they hatch from eggs at the very bottom of the Mariana Trench, but as the episode progresses they attempt to make their way to the Great Barrier Reef, but as they begin their odyssey they encounter many marine beings that threaten their lives such as giant squids, angler fishes, pacific viperfishes, giant spider crabs, six-gilled sharks, stingrays, etc. They once even hide in a brine pool to hide form predators out of desperation. Despite never meeting anyone else but themselves, the four organisms were biologically wired to seek out their friends and family, and they eventually make it to the reef and unite with them. In the last five minutes of episode, the four main characters begin to follow an amphibian creature in the ocean, and it had just evolved from a form of fish. The amphibian then made its way to the surface, with the four main characters clutching onto its tail, with all the organisms following their lead. The organisms then evolved into humanoids that strongly resemble their modern descendants, and then crawled onto land with the amphibian leading the way, until it is crushed by a Tyrannosaurus.

Trivia

 * The 2D hand-drawn animated sequences for when the characters were underwater were produced by both Neko Productions in Burbank, California and South Park Studios. The episode combines traditional animation with computer animation for when the characters move onto land.
 * The animation also bears a striking resemblance to the cartoon segment in the opening scene of the "Minions" movie.
 * When the characters were underwater, they communicated using American Sign Language and conveyed using visual clues.
 * Years are actually going by while the characters are beneath the sea, and they change size many times throughout the story. When they first hatch from eggs in Challener Deep, they are are about the same size as plankton, and when they grow fins, they are about the size of of a pygmy seahorse, but slightly smaller, and hence why Cartman's ancestor was able to fit in the pouch of a sea horse. When the characters grow hands and feet when they reach benthic waters, they are about 4-7 inches tall. When they leave the ocean, they grow to their typical size for South Park characters.
 * When the main quartet characters were in the hadopelagic, abyssal, and bathypelagic zones, they had possessed a natural phenomenon that allowed them to glow in pitch-black conditions and help them navigate in total darkness. This is called bioluminescence.
 * When the characters emerge out of the sea, they communicate solely with grunts and growls. This is due to humans not developing a language system until about two millions years ago.