How can I make a special ability for my slugcat with Slugbase?

[chilly hull]

you'd need to write a code mod which implements said ability into the game for your slugcat

you can check #modding-resources for a few useful links, or #modding-dev for help

[next bobcat]

This article can get you started: https://slimecubed.github.io/slugbase/articles/template.html