Made for this blog post: https://evertpot.com/neko
Neko is a desktop pet originall written by Naoshi Watanabe for the NEC PC-8901. Kenji Gotoh created a Macintosh version in 1989, which has formed the basis of many ports.
Over 30 years later, here's a simple Javascript version. This version doesn't follow the mouse pointer around, and stays asleep unless awakened.
All the art is taken from Oneko, which is public domain. Thank you for Tatsuya Kato for creating oneko and Masayuki Koba for creating xneko.