Now that’s a thrashing. Thor: The Dark World, the second installment of the superhero-blockbuster franchise, ran away with the weekend box office, with $86.1 million in its opening weekend. Coming in at Nos. 2 and 3 were Bad Grandpa, from the makers of Jackass, with $11.3 million, and the animated Free Birds, with $11.2 million. Last Vegas (better known as The Hangover for sexagenarians) and sci-fi epic Ender’s Game fell to fourth and fifth.