Winterbolt is the villain of the made-for-TV movie Rudolph and Frosty's Christmas in July. He is an evil snow sorcerer who, prior to the start of the movie's events, brought blizzards and snowstorms upon the North Pole. He looks somewhat like an evil version of the Winter Warlock before his redemption, or Saruman from The Lord of the Rings. When Lady Boreal came face to face with Winterbolt in human form, she used her powers of light to place him in a very long slumber.
Many years later, Winterbolt awakens from his eternal sleep and prepares to spread chaos and sorrow once again. When he hears that Santa Claus is the new king of the North Pole, he comes up with a sinister plot to eliminate him by conjuring up a snowstorm for Santa to get lost in. His attempts were foiled, however, when Lady Boreal passed whatever magic she had left to the newborn Rudolph, giving him his glowing red nose. When Winterbolt created a storm of fog and ice, Rudolph's nose lit the way (as seen in Rudolph the Red-Nosed Reindeer).
Winterbolt eventually discovers how Rudolph's nose foiled his plans that year and attempts to extinguish it. Pretending he wants to help, he tricks Rudolph and his friend, Frosty, into agreeing to make a special appearance at a circus in Florida. He then employs Scratcher to trick Rudolph into giving the circus' money to Sam Spangles, the evil carney who's trying to buy and take over the circus. Then, after Rudolph's nose is extinguished because of this act, Winterbolt also tricks Frosty into giving up his magic hat.
At the end of the film, Winterbolt is defeated when Lilly Loraine throws her airsoft pistols at his ice scepter, destroying it. When Winterbolt's powers die, he turns into a tree. This makes Winterbolt a rare instance of a villain in a Rankin/Bass holiday special who is actually killed off onscreen.