DreamWorks Dragons (2012)

S1E13 When Lightning Strikes

Unexpected lightning storms threaten the people of Berk, and the villagers believe they have incurred Thor's wrath. Mildew stirs up their superstitions, accusing Toothless, "the unholy child of lightning and death," of being the source of the storms. As panic spreads, Hiccup takes it upon himself to uncover the real reason behind Thor's furious behavior and clear Toothless's name.