Grandsanta's pet reindeer is a supporting character in the 2011 film Arthur Christmas.
He is Grandsanta's elderly pet reindeer who travels with his owner, his grandson Arthur and an elf named Bryony via Grandsanta's old sleigh Eve (pulled by the great-great-grandchildren of Santa's original eight reindeer) to deliver a bike to a young girl named Gwen after it is forgotten accidentally.
He is mentioned to have pulled Grandsanta's sleigh Evie during his time as Santa. He briefly does this again after the group lose the other reindeer.