Every bossbeast has the same level as the highest beast. This increases the attributes of it and makes the bossbeast very strong. "Melee" bossbeasts will only attack your protectbase on contact. "Ranged" bossbeasts attack your towers until everything is demolished on it´s way to your protectbase. Bossbeasts with type "Both" will have a non direct ranged attack and move straight to your protectbase to deal contact damage. Contact damage will always kill the beast directly without the earnings on death, because it´s an attack. You don´t need to kill the bossbeast to win the map. If you have more Healthpoints on your protectbase than the contact damage you will survive the bossbeast. Same as a usual beast.