4. Dark Phoenix Obliterates Xavier
When Jean Grey is discovered to be alive in the third X-Men movie (having been thought dead following the events of the second), she is taken back to the X-Mansion where she regains consciousness - but she is clearly not herself, she is the Phoenix. She tries to seduce Wolverine, asks him to kill her, then attacks him before retreating to her childhood home to find solace. Once there, she is followed by both the X-Men and The Brotherhood of Evil Mutants, who start a fight while Charles Xavier and Magneto try to convince her to join their respective sides. When Xavier tries to block her powers to revert her back to being Jean, the Phoenix gets enraged and unleashes all her might, firing everyone else away, destroying her home and easily killing the powerful Professor by completely obliterating every atom in his body.