“It was just difficult to figure out where I was going to come from with Superman ,” Gunn said speaking to io9 in Los Angeles last week. “And I think that it really started with my dog in a lot of ways. The idea of putting in Krypto, I think, was the fun part for me, because that was something that we hadn’t really seen in a Superman movie.”

The new Superman movie is almost here, but one scene didn’t make the final cut. According to the stars of the film, a moment involving Krypto, Superman’s dog, was removed after it didn’t sit well with test screening audiences.

A new photo book, with an introduction by James Gunn, offers a behind-the-scenes look at the making of the new Superman, out this July.