Mysterious Stranger

As long as Mysterious Stranger is under your
control, creatures you control get +2+1 when blocking.
Whenever you create a treasure token, create 2 treasure tokens.
Each land you own becomes a {b/g} or {b/r}.
Each time an instant or sorcery would affect
only this card, roll a d20, on 15+ it is countered.
Mysterious Stranger is exiled 3 turns after it was summoned. It cannot return to the field by
any means and the effects end.