A Hop Jack is the Ghouled version of the Hop Rock. These Ghouls are gray, and have brown backs with yellow bulbs. The Hop Jack also comes in a blue and red-coloured form, which is stronger than the brown and yellow version. At 100mph, they emit a high pitched screech, and become a sickly yellow, with a blue, spiky helmet. They also have pointed teeth, claws and a clubbed tail covered in thick spikes. Hop Jacks are more explosive than their normal counterpart and are commonly used by Dr. Blakk's henchmen.
- Protoform Abilities - Firecrackers.
- Skizzler - Sizzles as it flies, producing a medium-sized explosion.
- Blastfield - Lays small sparking balls as a proximity mine field - an opponent's first trip causes a chain reaction.
- Shrieknel - Explodes in front of an opponent- one large explosion followed by multiple smaller blasts.
- Blastrap - Morphs into smaller balls to form a floating explosive minefield around an opponent.
- This is the only Ghoul to have a complete design change in season 2.
- The Hop Jack Mega Morph looks a lot like the Greneater.