In the film, he is described as having golden-brown coloured fur, and a rapier as long as his own tail; the same as Reepicheep.
Little is known about Peepiceep, other than he was Reepicheep's second-in-command, and that he was an extremely brave and honorable mouse (a trait that is apparently common with all Narnian mice), and was most loyal to his leader, and to Aslan.
He was born sometime during the Telmarine Age of Narnia, and eventually became the second leader of his tribe. He followed Reepicheep everywhere, and so when his leader swore his allegiance to Caspian X, so did he.
He fought at the Second Battle of Beruna with Reepicheep and the other mice, during which Reepicheep's tail was cut off. When the mouse leader asked Aslan to restore his tail, and it appeared Aslan was not going to do so, Peepiceek said that if Aslan refused then he and the rest of the mice would cut off their own tails as well, wishing not to shame their leader. It was this display of loyalty that moved Aslan to restore Reepicheep's tail.
Peepiceek continued to serve Reepicheep, and Caspian X, and helped bring peace during the new king's reign. When Reepicheep and Caspian left for their voyage on board the Dawn Treader, Reepicheep left him to rule over the Narnian mice until his return, but he never did. When Reepicheep was on Ramandu's Island, he decided not to return, and officially named Peepiceek as his successor as the leader of all the Talking Mice of Narnia.
It can be assumed that Peepiceek lived the rest of his life in Narnia, fulfilling this role, until his death.
He also took part during the Telmarine Castle Night Raid, where he, Reepicheep and the other mice sneaked into the castle-tower, bound and gagged a cat, took down a couple of guards, and helped lower the drawbridge for the other Narnians.
- Peepiceek was voiced by Sim Evan Jones in the Prince Caspian film.
- Sim Evan Jones also did the voice for one of the wolves in The Chronicles of Narnia: The Lion, the Witch and the Wardrobe (film).
- Sim Evan Jones is also the film editor for both the Prince Caspian and The Lion, the Witch and the Wardrobe films.