Some mutants have the ability to drop Category 5 Hurricanes on major cities or manipulate the minds of the human population or rip holes in the Electro-magnetic field of the planet.
So, if mutants were real and lived on our world, which mutant ability would terrify you the most?
As much as I would love to have his power, I would fear Professor X the most. (this also includes other telepaths like Emma, Jean and Psylocke). I couldn't deal with them with my control issues. LOL