Kristoff Wears Sven’s Mom
In Frozen, when we first meet ice harvester Kristoff, we see him with a young Sven. This rather dark theory suggests that Sven’s mom was killed by ice harvesters and her pelt was turned into the coat that little Kristoff (and later older Kristoff) wears. Creepily, this would explain why Kristoff and Sven are so close. Not only did Kristoff raise Sven, but he did so while wearing his mom’s skin. Using reindeer pelts for clothing is popular in Scandinavian cultures.