The Black Infection

The Black Infection is something that can spawn in the forest.

If you kill a mob that is infected it can drop an infected key, infected bone or an infected eye. You have to collect 3 keys to unlock the secret temple. To find the secret temple you need to craft a infected compass that will lead you.

You need 3 infected eyes and 4 infected bones to craft the compass.

If you defeat the boss you get a potion that will help you avoid the infection yourself.