Have attached latest.log and crash-2024-05-26_19.42.09-fml.txt.

Can be reproduced by launching minecraft client-side with all three of these mods (and dependencies) installed.
Before reaching the title screen an error appears: org.spongepowered.asm.mixin.transformer.throwables.MixinTransformerError: An unexpected critical error was encountered

Minecraft 1.20.1
Forge 47.2.20
mowziemobs-1.6.4.jar
BOMD-Forge-1.20.1-1.1.1.jar
crittersandcompanions-1.20.1-2.1.6.jar

Please try this test version instead! And let me know if the problem goes away.
https://legacy.curseforge.com/minecraft/mc-mods/mowzies-mobs/files/5380391

Try the spawn eggs instead!

Hi! Yes this seems to work, I could succesfully launch and load into game. I managed to summon the sunbird mobs succesfully, but baby foliaath and frostmaw didn't appear when I used /summon- this was probably where I was summoning them though, as I did it above ground in daytime idk?

Also awesome mod :))

Sorry for the slow reply, it works with the spawn eggs :)