Scrat is an acorn-obsessed saber-toothed squirrel that lived during the ice ages, attempting to store his prized acorn. As of 2013, he became the mascot of Blue Sky Studios, a subsidiary of 20th Century Fox (Now owned by Disney).

During the days of the ice age, Scrat took an acorn with him everywhere, hoping to find a place to store it for the winter. Scrat also went out looking for other acorns so as to further his storage, looking all over for acorns and nuts.

Scrat went on fixated with taking his acorn until he met another saber-tooth squirrel named Scratte, who Scrat fell for, forsaking his acorn for a time until he grew to miss it and returned to his acorn, leaving Scratte behind in a world of dinosaurs.

Further on in time, through a mistake, Scrat was responsible for the separation of the continents, which divided Pangaea, the singular landmass, into various continents. After this, Scrat found a paradise on Earth for himself: an island populated by advanced saber-tooth squirrels known as Scratlantis. After finding it, however, Scrat sunk it by mistake, stranding himself in a North American desert.

After sinking Scratlantis, Scrat wondered through the landscape with a new acorn in hand. He ended up falling through the ice into a cave. There, he ended up finding a place to finally store his acorn. Apparently, his acorn ended up powering a UFO that was encased in the ice. After confusingly moving the lever, Scrat managed to blast out of the ice and into the cosmos. Up in space, Scrat ended up creating The Solar System, rearranging the planets and causing a collision between two planets creating the asteroid belt. When the UFO rammed into a giant asteroid, Scrat ended up burying his acorn once again. As Scrat had finally managed to store his acorn successfully, the asteroid ended up cracking and made it's way towards earth. Scrat had once again put the earth in danger because of his obsession over his acorn. Later on, Scrat had no control over his UFO, and ended up crashing on Mars, which had similarly looked like Earth, wiping out all vegetation, water and other life form on the planet.

At some point in his future, Scrat was frozen in ice and survived the ice ages, some twenty thousand years later, washing up in a block of ice on a tropical beach. Scrat lost his acorn and found a coconut, which he treated the same as his acorn, though in storing it, Scrat started another cataclysm by mistake.