Listen to the Stinker Madness Episode
Watch the Whole Movie!
Some little dudes who clearly aren't actual Ghoulies warp into our dimension again to do...something... All while the guy from the first Ghoulies is still dealing with his demon summoning past and his obvious hot-chick magnetism, despite now being one tough cop.
So the first thing that should be noted is that there are no ghoulies appear in this film. We're told that there is ghoulies but these are clearly not ghoulies. And there's only two of them. And there doing very not ghoulie things. We think they likely were not warped in from Purgatory but from Nilbog.