Long ago, during a period of particularly hot temperatures, known as Paleocene-Eocene Thermal Maximum, snakes were enormous, in some cases as long as a bus. Partial skeletons of such nightmarish creatures, dubbed Titanoboa, were actually discovered in Colombia, revealing a hellish past where reptiles were once much, much larger than they are today. In fact, a new study claims things could get that way again if temperatures keep climbing worldwide.

About 60 million years ago, the warmer temperatures played a strange part in reptile and mammal size; reptiles were much larger, while mammals, such as horses, were once much smaller. Evidence of such a phenomenon has been found at the Cerrejon Mine in Colombia, which is thought to be a hotbed for fossils from the Paleocene Epoch period. Today, coal seams at the site are said to be so active that they can spontaneously combust, NBCNews wrote.

According to paleontologist Jonathan Bloch, fossils of breakfast table-size turtles have been discovered, along with the aforementioned Titanoboa. "Imagine that the snake would have to squeeze through the door, and come up to your waist," Bloch said. Repitles, known as ectotherms, depend on environmental conditions to regulate their heat; if temperatures were particularly hot between 65 and 56 million years ago, they may have grown to gargantuan sizes.

On the flip side, Bloch and other researchers claim ancestors of modern-day horses were as small as house cats during the same period. Imagine the Kentucky Derby being run by horses no bigger than grumpy cat. Similar to a snake's response to environmental conditions, mammals may have found it more difficult to regulate body heat back then, while less nutrition from plant sources was available because of the hotter temperatures.

Bloch claims current atmospheric carbon dioxide levels are on their way to reaching Paleocene-Eocene-levels, which, if history is anything to go by, could lead to some giant snakes in the very distant future. Bus size snakes. Just think about that. And you thought the movie Anaconda was cheesy, it may have a look into the future.