Burnt Boys are enemies that appear only in The Rapture. If you get close enough to them, they will chase after you. They mimic Meat Boy jumping when he does. They can be killed by anything that can kill Meat Boy, except for another Burnt Boy. Also, they tend to move randomly sometimes, making them one of the RNG-based things in the game.
There is a glitch with them which makes them walk much faster than Meat Boy when walking on sloped surfaces. When they are on slopes, they move faster than Meat Boy can.