Daily Dose of Prehistory: Back From Extinction 22

Homotherium serum, which means "Same Beast", is an extinct genus of machairodontine sabre-toothed cats, often known as scimitar-toothed cats, that lived in North America, South America, Eurasia, and Africa from around 4 million years ago to around 12000 years ago. About the size of a male African lion, Homotherium was much more lightly built than other sabre-toothed cats of the time while also having longer, slimmer limbs, a sloped back, and reduced claws suggesting it was an endurance runner like wolves or humans. Like the modern-day cheetah, Homotherium had a large and complex visual cortex, suggesting that it was more active during the day than at night like most other cats. From fossil sites like the Friesenhahn Cave in Texas (where the remains of nearly 400 mammoth calves and several dozen Homotherium specimens including elderly and young animals), it can be inferred that Homotherium's favored prey were young proboscideans.

This one sounds like an experimental gay cure.