Dr. Fetus

Dr. Fetus is the main antagonist in the game Super Meat Boy. Made obvious by his name, he is a small fetus in a jar. Despite his name he is not a real doctor. He is Meat Boy's arch nemesis, and will do anything he can to make sure Meat Boy dies. In the opening to the game, he beats up Meat Boy and kidnaps Bandage Girl, which means Meat Boy needs to save her. During gameplay when Meat Boy catches up to Bandage Girl, it only ends up with Dr. Fetus kidnapping Bandage Girl and teleporting elsewhere.

In Super Meat Boy
Not only does Dr. Fetus act as the main antagonist in the game, but he also serves as some of the bosses in the game. Whether it was a creation he made, or something else. The first of his creations was Lil' Slugger, a gigantic walker mech with a chainsaw at the front which was fought in chapter 1. He uses it to chase down Meat Boy, but ended up crashing it into a wall and it broke down. Another one of his creations was Brownie, who was a monster who had an appearance similar to Meat Boy, but instead of being made of meat he was created with Dr Fetus's feces, who was fought in chapter 3. However not long after Brownie was created, Dr Fetus activated a trap that caused the Salt Factory they were both in to rise, in an attempt to drown them both in salt. Meat Boy survived, however Brownie did not make it out alive, as he was pelted with bricks thrown by Dr Fetus.

In the final chapter, Dr Fetus is fought as the final boss of the game. The player must run from Dr. Fetus, avoiding the plethora of saws, pits, Dr. Fetus' missiles, and the two saw "columns" hanging from the top of the "castle" that Dr. Fetus controls, that kills the player if they wait around for long enough on any area of this section of the battle. Then the player is trapped in a room with Dr. Fetus. There is a switch at the top of the ceiling. The player must dodge the missiles shot from Dr. Fetus and hit the button. Then the player must run into another room and the floor will collapse, resulting in Dr. Fetus falling into a pit. When he lands, his glass jar will break, revealing his body completely. As he rolls around in pain and Meat Boy finally reunite with Bandage Girl, he will press a button, causing his "castle" to start falling apart. Then the player must go all the way back through the level, although with some notable tweaks, such as black smoke and a lot of shaking, making the escape arguably just as hard, though the saw columns "magically disappear" in a way that is never really explained after the player reaches the end of the first half.

in Super Meat Boy Forever
After being presumably defeated in Meat Boy's first adventure, Dr. Fetus is said to make a return in Super Meat Boy Forever, presumably having the same roles as well. In the trailer for the game he is seen kidnapping Nugget, Meat Boy & Bandage Girls's "ltittle bundle of joy". When Meat Boy and Bandage Girl saw what happened, they knew what they had to do. Apart from this information, not else is known what roles Dr. Fetus will have in the game, as it is yet to come out.