Minecraft/Zombie Seige

A zombie siege is when zombies spawn in large quantities within a village. The only variant of zombie that can spawn is a baby zombie. Zombies that spawn during the event behave more aggressively than other zombies and will ignore sunlight. Every night, at midnight, if you are in a village, there is a 1 in 10 chance of one starting. Once it starts, 20 zombies will spawn within the village and start to attack the villagers. Lighting up the village perfectly and on every block, and surrounding it with a wall will not protect the village from a siege.