I just finished making this zebra sackboy for my 3 year old.
It is his first sackboy. I've made his big brother 5 of them (that look different).
For his mane, I crochet into some of the knit stitches, chained 5 to 11 stitches, and single crochet back down the chain stitches. Then I repeated this until I reached about a half an inch above the back of his neck.
I'm really happy with this zebra version and so is my son.