When a outbreak of Eel Pox came to Berk in "The Eel Effect", Hiccup and Toothless went to Eel island to retrieve the final ingredient for the Eel pox cure; a bloodvein eel. However, when Hiccup fell into one of the eel-infested streams of the island, Toothless leapt in and rescued him by unintentionally eating the eel that was attacking his rider. Following that, Toothless experienced the symptoms of eel pox and attacked Hiccup. When Fishlegs and Meatlug arrived to assist Hiccup, they found out that the Island was home to wild Typhoomerangs due to them being the only dragon that eat eels. They managed to cure Toothless before returning to Berk to heal the ill Berkians.