Ice Age A Mammoth Christmas is a 2011 computer animated television special and part of the Ice Age franchise, produced by Blue Sky Studios and directed by Karen Disher. It premiered on November 24, 2011 on Fox and it was released two days later to DVD and Bluray.
Christmas has come and Scrat eyes a beaver assembling a cache of foods, among them an acorn Scrat sneaks in and takes the acorn, along with others he finds in the area set up as decorations he ties a large stockpile of them on a piece of bark and tries to leave with them, but they break out and leave him with nothing. Meanwhile, Manny brings the Christmas Rock out of storage, to Ellies delight the rock is intended as a surprise for Peaches, who comes sliding down a snow slope in a snowball fight with Crash and Eddie. Manny reveals that the Christmas Rock is the same one from his childhood, a family heirloom, and important as it lets Santa Claus find them to deliver presents.Diego and Sid step in to see the Christmas Rock, with Sid deriding it. Manny will not let Sid near the Rock and Sid, to find his own means of decorations, decides to find a different decoration and chooses a tree. Crash and Eddie help him to decorate the tree with insects, small animals, and fish bones to top the tree, Sid puts a starshaped piece of ice on the top, which is accidentally flung off and hits the Christmas Rock, shattering it. Manny, furious at Sid, declares that Sid is on the Naughty List. Manny dismisses the idea of Santa to Ellie, which Peaches overhears, and the young mammoth is shocked that Manny does not believe in Santa. Sid, in tears that he destroyed the rock, slides downhill as his tears freeze solid. ........
Source: Wikipedia