This mod for Minecraft adds a vengeful variation of the cow that will relentlessly attack you when you get too close. It only spawns at night in groups of 1-3.
The attacks of the cows:
- Shooting arrows at you for decent damage
- Biting you if you touch it
If they fight you with other mobs trying to attack you, they can actually overwhelm you and kill you, even in unenchanted full diamond armor.