Some players on my server have been experiencing crashes triggered by them killing a tamed Mo' Creatures mob, which seemingly tries to store some Mo Creatures NBT in the Morph player capability data in the player's NBT file. This causes the players affected to experience crashes when they open the morph menu or attempt to morph at all. The stack trace from one player is located here: https://hastebin.com/ugarodazik.txt

Killing untamed Mo' Creatures mobs works fine and they can be morphed into, but if they are tamed, it causes this crash. It seems Mo' Creatures is expecting there to be more data associated with tamed animals that is not stored in the morph capability data.

So... what is your suggestion to fix it? 🙂

I see the problem, but all I can say is that it's a mod incompatibility. Stuff like that are quite tricky to solve, and I've got no time for this.

If I were to fix it, I'd probably put more limits on which NBT is stored in morph capability data. It's obviously difficult to tell which NBT is the offending NBT without being able to see the source for Mo Creatures...it would almost be easier to hard-code special cases for offending mods with some sort of abstraction layer when storing the morph NBT but of course that's not really a minor fix. If I have time I could make a PR to try and fix it.

Good idea, I will try to add NBT stripping fields to morph configuration

was this done ?