[@Cassowarysaur]
[hider=The Spoilening]There is an underlying theme regarding the whole magical girl thing that is yet to be revealed, so there is a thematic justification for the genre shift, though there have been hints of it in previous episodes (the creepy witch worlds alongside mystery girl's ominous speeches). There's also an in-story justification for Mami's death: she was cautious and careful in her battles due to being lonely, but Madoka's influence caused her to become more happy, and thus, more careless in her fighting, resulting in her getting chomped. It was also stated by Mami that fighting Witches is dangerous business.[/hider]