Frozen UFO

The Frozen UFO was a flying spacecraft that somehow got frozen while flying.

History
While the UFO was flying, it got frozen somehow, being preserved in ice for a long time, along with frozen animals and other creatures.

Sid noticed the frozen UFO just before the baby Neanderthal, Roshan, got to the ice slide.

The UFO made a reappearance in the 2015 short film Cosmic Scrat-tastrophe and will be used as a plot point for Ice Age: Collision Course.