In How to Train Your Dragon 2, Eret later rides the dragon named Skullcrusher.
Eret, Son of Eret, begins the film as a dragon trapper working under Drago Bludvist. After recognizing that Drago’s methods threaten both dragons and people, Eret changes sides and joins Hiccup’s allies. Skullcrusher is a Rumblehorn who becomes associated with Eret after Stoick’s death.
This fact is easy to mix up because Stoick rides Skullcrusher earlier in the film. Eret does not begin the story with this dragon as his established companion. The changing rider reflects the film’s themes of loyalty, responsibility, and the possibility of changing one’s path.