ShiverJack is an antagonist from the Disney Junior show Jake and the Never Land Pirates, serving as the eponymous main antagonist of the episode "ShiverJack". He is known to be truly evil and dangerous, even much more ruthless than Captain Hook (the main antagonist of the series).
He was voiced by Mark Hamill, who also played The Joker in Batman: The Animated Series, the Skeleton King in Super Robot Monkey Team Hyper Force Go!, Maximus in the Fantastic Four animated series, the Hobgoblin in Spider-Man: The Animated Series, Kavaxas in Tales of the Teenage Mutant Ninja Turtles, Stickybeard in Codename: Kids Next Door, Flint in Disney's Buzz Lightyear of Star Command, Niju in Balto II: Wolf Quest by Universal Pictures, Solomon Grundy in the DC Animated Universe, Dr. Pullum in Dan Vs., Fire Lord Ozai in Avatar: The Last Airbender, Trickster in The Flash, Dictatious Maximus Galadrigal in Trollhunters, Undergrowth in the Danny Phantom series, Agent Goodman in Disney's Recess: School's Out, and Alvin The Treacherous in the How to Train Your Dragon series.
When ShiverJack made his debut, he put Belch Mountain on a good freeze, as well as a beach including a monkey trying to eat a banana as part of his plan to make Neverland his frozen domain.
He even put the freeze on Captain Hook and his crew, and later put the freeze on Izzy, Cubby, and Captain Frost. He froze Skull Rock to complete his mission, but this is short-lived when Jake, Skully, and Captain Flynn used a Heat Cannonball to defrost all of Neverland with the help from a magical orb containing the magical Never Winds that can melt the ice away.
As such, Neverland is freed from ShiverJack's control and everyone is defrosted (including Captain Hook). Despite being defeated, Shiverjack angrily vowed to return to Neverland more colder than he was before, just as he vanishes away.