The End of All Reality

All mana you produce becomes colorless. You may spend colorless mana as if it were any color (excluding generic mana) for free, up to the number
of Insight counters on permanents you control. Beyond this limit, whenever you use colorless mana in place of colored mana, you must target yourself or a creature you control and deal 1 damage to it.

{t}, {w}{u}{b}{r}: The effects of this card now apply to your opponents until your next unkeep. They can only target themselves.