Paragon

After a certain amount of mobs of the same type are killed, there is a chance that a Paragon mob will spawn. This mob will have a different visual effect upon spawning and will have the word "Paragon" above it's head. It will also appear to be slightly larger than the rest of the same type of mobs. This mob will have more HP, hit harder, and upon its death, will drop a "Paragon Chest" that will contain special loot and will require someone to lockpick it open to access the special loot.