when your at the castle that the monster is at, go down and to the right a little. you should see a couple of boards bunched together so they form a raft in a hole thinggie, then you use your cloud pencil to fill the hole with water, should only take a couple of tries, then you go down the waterfall on the raft, you can take the Frankenstein monster with you for a achievement, you should also be able to get a page.