I based this from various patterns:
Nerdigurumi’s Link pattern for the head
Geisha-Neko’s tutorials for removable shirt and removable pants

Prior to this I only made one amigurumi of a cat based on Lion Brand’s cat pattern.

The hair was made from felt, sewed on by my sister. But the rest was crocheted by me. You could read the details on my blog entry: Amigurumi - Hiyama Kiyoteru