On The Hive level, the Boss will be a giant leech. To kill it easily, make it chase you back to the start, where you first get on the boat. Once there, hop out of the water and shoot him (if you have ammunition). If you do not have ammunition you can use the steel pipe, broom, crutch, or knife to kill him. If you are using the knife, you can either hop back in, stand in front of the giant leech, then stab; or you can stand out of the water and use the knife. When you stand outside of the water you will not be able to hit the giant leech until it lifts up its head. You must then stab quickly; you should be able to get two or three stabs. If you are in the water fighting the giant leech, you can get a few good swings at it, but be careful -- it only shoots acid when it is stuck there. It also swings its head back and forth causing damage to your character. Note: Though this is a very easy way to kill the giant leech, you must also watch your partner's health. Your partner can die from the giant leech, and if that happens your partner will turn into a leechman.