I seem to recall reading somewhere that the game generates content on a region-by region basis, so one could theoretically turn this mod on to get a region free of Hulks, and Brutes, then once they feel prepared, remove the mod from the mods file in the world data (where the executable for the game is stored you’ll find a myriad of folders, one of which will be titled “save” or “saves” [I forgot which], inside there you’ll find one or more folders named after your world(s), and inside that you’ll find files containing data relevant to the world the folder is named after).
After removing the mod from that file (I believe the file is just called “mods.json”, but it’s been a while since I peeked inside a world’s folder) all future content in that world should spawn without the mod applied, so you’ll have Hulks and Brutes again. If you have wander, or dynamic spawns on then you may start seeing them immediately depending on how those systems work, if not then you might see them in the next region generated. I’m not really sure how large a region is, but if you go far enough in a particular direction then you’ll end up in a new one.
This is all just conjecture, I’ve never tried it myself, so I can’t be certain it will work, but I see no reason (in my admittedly limited experience) why it wouldn’t.
