Use toilet paper rolls as a sturdy base for larger cosplay horns, taping them together before covering with foam clay or papier-mâché.
Attach finished horns to a headband, mask, or hair clip using wire or hot glue. Paper Halo Craft Guide
Cover a wire frame (or tin foil base) with newspaper strips dipped in a mix of cornstarch and water (or school glue) to create durable, customized shapes.