I was reported this crash: https://pastebin.com/7pYpUTRL after leaving a portal with a bat morph.
I'm not sure whether this is an issue with the mod as I was unable to reproduce it on the first try, but I thought I should forward it nonetheless.
Thank you!

As Morph has just been rewritten and released for MC 1.16.5, I am clearing the issue tracker as I have not provided any support Morph for 1.12.2 and earlier. My apologies for not addressing your issue.