when I try to shrink it won't let me it just kills me I don't know why is it even possible to fix it?

I am having a similar issue, when I die after my second shrink, my game crashes, I am testing some mods before I put them on a server I can't make sense of the crash log so I'll link it to this comment here.

me and my friends are using origins on a aternos server, i have the slime origin but i still can't seem to shrink, it just kills me or kicks me from the server, is there a specific version i need on the aternos server or do i need to install something else?

Check on the newest updated, and make sure you have Pekhui installed