In Ice Age: Collision Course, the asteroid-warning character voiced by Simon Pegg is Buck.
Buck is the one-eyed weasel introduced in Ice Age: Dawn of the Dinosaurs. In Collision Course, he returns after discovering evidence that an asteroid is heading toward Earth. His warnings initially seem eccentric to the herd, but his knowledge of prehistoric dangers becomes essential as the characters search for a way to prevent the impact.
Simon Pegg has voiced Buck since the character’s debut. The role combines frantic scientific speculation, physical comedy, and Buck’s established bravery. The film expands Buck’s earlier identity as a dinosaur-world adventurer by making him central to the planetary-threat plot.
The character should not be confused with Rudy, the giant albino Baryonyx from the third film, or with Gutt, the pirate captain from Continental Drift. Buck is the small mammalian adventurer whose discoveries drive the fifth film’s story.