In the 1964 Rankin-Bass TV special "Rudolph, the Red-Nosed Reindeer," Rudolph's dad was Donner (voiced by Paul Kligman); in the 1998 GoodTimes Entertainment animated feature "Rudolph the Red-Nosed Reindeer: The Movie," Rudolph's dad was Blitzen (voiced by Garry Chalk). Neither the original poem by Robert L. May nor the later song adaptation made any reference to Rudolph's dad.
Donner and Blitzen are both reindeer who were listed in the 1823 poem "A Visit from St. Nicholas." Some printed versions of the poem spell their names as "Donder and Blitzen" or, as the line appears in the original 1823 version, "Dunder and Blixem." These spellings are based on the German and Dutch words meaning "thunder" and "lightning."