Psychic Allergy {3}{U}{U}
Enchantment
As Psychic Allergy enters the battlefield, choose a color.
At the beginning of each opponent's upkeep, Psychic Allergy deals X damage to that player, where X is the number of nontoken permanents of the chosen color they control.
At the beginning of your upkeep, destroy Psychic Allergy unless you sacrifice two Islands.