You need OptiFine 1.13.2 HD U G5 (or higher version) to make this resource pack work properly.

CMM 1.13.2 VB_1.4
New:
- snow golem , endermite , Silverfish Model can now walk.
- Fixed cat model bugs.

credit code ( twitter: @gorienchis )// thank you so much =w="
https://twitter.com/gorienchis/status/1347513428227735557