rough mobs is a mod that focuses on increasing the power of hostile mobs in Minecraft, either by increasing their health, attack, defense parameters, or by increasing the likelihood that these mobs will be equipped with weapons and higher level armor, and even enchanted ones.
Some examples of these changes are: Creepers which are much faster and become invisible when close to the player, Endermans which can apply blind or nausea effects to the player, among many others. The entities modified by the mod are: Creppers, Zombies, Slimes, Skeletons, the Wither, Endermans, Zombie Pigmen, Silverfish, Blazes, Magma Cubes and the Ghasts.