The Ordovician period was home to six-foot sea scorpions, giant squid-like cephalopods with towering shells, and countless trilobites. But it also marked the first mass extinction in Earth’s history, wiping out 85% of all life. For the first time, animal life faced a global collapse on an unprecedented scale. The cause? A dramatic shift from intense global cooling to rapid warming. It was a devastating one-two punch. Full series on Colossal's YouTube. | Colossal Biosciences