Seeing monsters
When Anna and Kristoff go to find Anna and get her to leave her ice palace she, rather impressively, creates a giant snow monster to scare them off (if only we all had that power!). Called Marshmallow, after order is restored in Arendelle, he retires to Elsa’s ice castle and lives happily.
His legend obviously traveled much farther than Arendelle. All the way to Polynesia, in fact. In a scene from Moana, you can see a tapa cloth in one of the village’s huts that blatantly depicts Marshmallow. Maybe Moana heard about this terrifying ice monster when she was a little girl, sitting on her father’s knee. To a girl living on a tropical island, an ice monster must have seemed very exotic.