I love all the creative costumes on this site! Of all things, my son asked me to make a hippo costume for him last year. I couldn’t convince him to be a ghost. :) When I couldn’t find any hippo patterns, I used a Simplicity BIRD pattern 3663 and modified it to make a hippo costume. I had to add ears, make the “beak” bigger so it looked like a hippo mouth, add big teeth, change the tail, and add “toes” to the arms. It’s by far the fanciest costume I’ve ever made! But the Simplicity pattern was easy to follow. My son loved it and it was a hit while we were trick-or-treating. I wrote out the exact modifications I made in case anyone wants to try to make a hippo costume too!