Amigurumi is the Japanese craft of crocheting or knitting small, stuffed toys — animals, dolls, and characters. It's worked mostly in tight single crochet in a continuous spiral so the stuffing stays hidden inside.
The word combines the Japanese ami (crocheted or knitted) and nuigurumi (stuffed doll). Amigurumi typically starts from a magic ring and uses a hook one size smaller than the yarn label suggests, which keeps the fabric dense enough to hide the stuffing.