I pulled a mythic rare Iona, Shield of Emeria from Zendikar pack cant wait to use it it is powerfulit has 7/7 and flying and it also has this:
As Iona, Shield of Emeria enters the battlefield, choose a color.
Your opponents can't cast spells of the chosen color.
If I choose "colorless" for color can i prevent all other players to cast land spells?