Wallopers are yak-like creatures that lives in different parts of Ninjago. After Morro possessed Lloyd, the ninja set off to Stiix by riding four the Wallopers Misako brought them. At night, the group was ambushed by Wrayth, who turned Cole's Walloper into a ghost walloper. Shortly after, the ninja traveled up the Wailing Alps, where they found another Walloper. Jay and Kai briefly quarreled over whether it was a yak, goat, or cow.
Kai wakes up to find a walloper licking his face and eating his noodles. The ninja rode their wallopers that to Stiix until Wrayth encountered the ninja. Wrayth also turned Cole's Walloper into a ghost before Jay shooed them off.
While climbing up the Wailing Alps, the ninja encountered a Walloper. Jay, however, believed it to be a goat, though after Kai claimed it was a yak, the Master of Lightning changed his opinion to it being a cow.
- Wallopers are based on yaks.
- "Wallop" means to hit something very hard. Presumably, "walloper" would then mean "one who hits something very hard."
- In "Ghost Story," Cole's Walloper turned into a ghost. This foreshadows the event where Cole himself turns into a ghost in "The Temple on Haunted Hill."