Brownie

Overview

Brownie is a boss character from Super Meat Boy made out of human feces. He was created from Dr. Fetus' bodily waste, by Dr. Fetus at the end of the Salt Factory stage through a machine that roughly resembles a smelter. He's extremely aggressive, strong and makes a hideous screeching sound. However, since he's made out of feces he's extremely gassy.
 

Tactics

Despite being created as a weapon to defeat Meat Boy, he doesn't get to do any fighting before Dr. Fetus floods the salt factory with salt. The battle with Brownie is actually a race against Brownie to higher ground. He moves, jumps and runs exactly like Meat Boy... with the exception that he leaves feces behind instead of blood.
 
After the boss battle, he nearly falls into the salt when Meat Boy grabs him. But before he can be pulled up to safety, Dr. Fetus throws bricks until Brownie falls into the salt, just to spite both of them. It appears Brownie dies until the end of the game where he appears to save Meat Boy from collapsing debris, sacrificing himself in the process.