Siris, The Blade Wielder

+3: Create an Infinity Blade artifact equipment with "Equipped creature gets +2/-1 and gains double strike" and Equip 3
-5: Siris becomes a 9/9 human knight creature with haste and protection from everything until end of turn. He is still a planeswalker.
-15: All creatures you control get +2/-1 and gains double strike until end of turn. Tap all creatures opponents control.