So my campaign takes place in an area of the continent where 3 lesser lords look over a city. Each species of monster that the lords are has its own homebrew gimmick.
Vampires reduce your maximum HP when grappling you to heal.
Werewolves didn’t change much, but they are weak to gold instead of silver for lore reasons (it also avoids metagaming a bit).
Now for the third… Aberrations.
The main gimmick I have is basically having them mess with the game in a way that no other monster does. For example, the first (and only) encounter my players have witnessed is when they had to fight a VERY weak one, but they almost died because the gimmick of that aberration was that it had no HP in the first round, instead it took twice the damage it was dealt in the first round and turns that into its HP, where the real combat starts at the beginning of round 2 (if they do less than 60, it would default to having 120 HP).
I just want more fun gimmicks like this. My players were horrified after going nova on it and realizing they fed it about 230 HP, and the whole combat was great.
So, any ideas?