The song is "I am a cat（わたしはねこ）"
Lyrics, composition, singing, and animation by Yukina Kita（北如来那）.
   • わたしはねこ/ 北如来那 Yukina Kita  
Yukina Kita's homepage
https://kitayukina.com/
Video List of Yukina Kita
   / @yukinakita  

My video list
https://www.youtube.com/@noho91/videos
My woodworking homepage　（のほほん木工房）
http://noho91.web.fc2.com/