Preventing a modded mob from spawning in forge 1.12.2 when the mod has no config file.

Hi, I recently started a minecraft server and I'm trying to stop this one mod from spawning these custom creepers in every dimension. The mod in question doesn't have a config file that shows up in my servers config folder. I just mostly want to know a good way to go about removing this mob from the mod or how to prevent it from spawning without a config folder. Also wanted to confirm if it would be possible to hard code in my own config file for the mod? Thanks!!