The climax of the movie has a giant snowman that rips out a tree to use as a nose.
Jack Frost's threats to lock Rachel and Kirsty in his dungeon for 100 years can become this when you remember that Time Stands Still in Fairyland. They'd return to the human world at exactly the same point as when they left...but they'd have lived through 100 years of imprisonment. And that isn't factoring in whether they'd age in Fairyland...
In Sky the Blue Fairy's book, just being near the goblins is enough to freeze Sky, nearly causing her to fade away. Rachel worries that the goblins have hurt Sky forever.
Lucy the Diamond Fairy's book has Jack Frost summoning icicles to rain down on the girls. The same book also has the fairies' flying magic fading, even Rachel and Kirsty's.
One scene in Charlotte the Sunflower Fairy's book has Rachel frozen solid in midair, and in danger of landing on the ground and shattering.
Ashley the Dragon Fairy's book has Sizzle's magic working in reverse on Rachel and Kirsty. Since Sizzle normally helps with imagination, the reversed magic drains them of all creativity and thought. Rachel describes it as a switch being flipped and her brain being emptied.
Autumn the Falling Leaves Fairy's book doesn't shy away from showing the consequences of what Jack Frost did. In trying to skip fall and go straight to winter, he created an endless summer where everyone is thirsty and food doesn't grow. This causes several human world animals to help Autumn because without her magic, they can't get food.
The climax also has a scary moment. The girls' plan to melt the Ice Castle works too well, and Fairyland is in danger of being flooded. Jack Frost, genuinely repentant, agrees to work together with Autumn to fix things, but Rachel and Kirsty can't stop thinking about it until they know things are okay.