Would LOVE this as well; although I get the feeling it would take a lot of time and energy to get it ported and continuously maintained (especially considering none of his other projects indicate that he has any experience with Linux).
It's definitely not a replacement, but if you're interested in cute desktop toys like this, (in case you don't already know about it) you might check out "Oneko". It's a program that adds a little cat and/or dog to your screen which follows your cursor around. That said, I've had mixed results running Oneko on Wayland.