3. He shot Hulk into space and caused World War Hulk
Admittedly, the Illuminati are collectively to blame for this. The Illuminati are a secret superhero group originally consisting of Namor, Iron Man, Mr. Fantastic, Doctor Strange, Professor X, and Black Bolt. They essentially made decisions in secret and tried to manipulate events, which is already quite questionable.
After Hulk had another one of his rage outbursts, Tony Stark wants to solve the problem with the other Illuminati. Tony suggests sending him into exile on an uncivilized planet. Everyone except Namor agrees, and Hulk is shot into space. He lands on the wrong planet, but builds a family there and frees the population from slavery.
Everything goes well until the spaceship he was sent in explodes, killing countless beings and also Hulk’s wife and unborn child. This leads to the event World War Hulk, where Hulk returns to Earth to take revenge on Iron Man and the others (Marvel Database).
