For those of you partial to the homemade approach rather than the mass market productions, consider Etsy for something the other kids are less likely to have.
Etsy seller Madhelmeteer has some great crocheted animal hats to provide a costume while keeping your child’s head warm.
Personal favourites include the Dino Baby, Roar With Courage and the tusked Elephant. While appropriate for Halloween I can see these being super popular for everyday use.
Etsy seller Funnyfinn comes through with a few fleece animal hat options as well.
Here my personal favourites are the Giraffe Helmet and the Monkey Helmet.