In muck there are 2 bosses at the moment of this guide.Big chunk and Gronkyou can choose either one of these but big chunk can drop Chunkium which can be turned into ingots that can be used for the chunky hammer or for Chunkium armour which is better than Mithril and gives 60% more attack range. Gronk can drop a sword which is the best sword/melee in the game.
How to get really good loot fast!!
Step 1: Load into a muck game and find a structure like a shack or a cart that has a
steel axe or pickaxe.
Step 2: Go to a pillar that spawns monsters during the day and activate it you will get a bit of gold (plus if you get gold in the chest from step 1 then thats great) and go to a chest costing 25 and open it. (you can also get free chests they are black)
Step 3: Find a Gronk or a Big chunk spawner they are statues of either big chunk or Gronk and they spawn what boss is on the statue.
Step 4: Spawn the boss and try not to get hit if you are battling Gronk go behind him and hit him or if its big chunk use the frog ability.
(Reminder) you may not get it first try but if you keep failing I suggest going to a lower difficulty or getting more upgrades