Corruption Outbreak

Corruption Outbreak is an event of the Abandoned Laboratory which occurs when corrupted specimen break out of the Chemical Lab. Those corrupted test subjects keep their manipulated body parts the player made, and can survive outside the Laboratory, possibly creating a catastrophe. Those subjects should be kept from leaving the laboratory at all costs, since they can spread their gene, if the Player wanted to weaponize those artifical species, it is the most dangerous scenario. You see, those mobs start spawning in the Corruption once they reach it, they do not despawn outside the view of the player, to ensure they can reach it. The subjects in the Lab are called by their codename, once they reach Corruption, they change their names to what they look like based on abilities and bodyparts (example, Corrupted Zombie spitting acid in the Corruption is named as a Vile Spitter). This variation of events is stopped once there are no more broken out subjects left.

But if a subject's genes are unstable enough, and they are powerful enough at base, once they reach the corruption, they start to mutate, possibly creating a boss.

There is another possible run of events, if the mutative subject reaches the bottom of the basement, where COR-MULTI previosly was, they have the possibility to become another boss (example, a mutative Eater of Souls reaches this place, starts mutating, and forms the Devourer of Souls, a giant flying monster with similiar behavior to a Wyvern in terms of it's body, but it fires acid as well, and can vacuum the player to bite them), making it the core of the outbreak, just like CO-MULTI. If this is defeated, then the outbreak stops.

However, if the broken out subject is a smarter version of the creature it originally was, possibly with Hivemind, then the outbreak might continue in an entirely different way, and with strong enough ability to learn and remember, possibly become a Nemesis to the player, evolving along the Player's progression if left unchecked. It's path depends on it's own mind. It possibly could utilize it's enviroment and materials around it, or become the leader of a Devouring Swarm, maybe even make a little civilization if it is smart enough, creating a Rivalry Situation.