So on the mod list you have Mo Creatures up to date on 1.12.2 perfectly fine, but its dependency, Custom Mob Spawner, is only up to 1.10 on curseforge, so you have to get it from the Dr Zharks Mo Creatures website. If you could add the updated version to the mod list from there that would be amazing, as I could finally use mo creatures on 1.12. Thanks for viewing!
The Download (mediafire) is //removed link if you need it.