A.027, Myr of Battle

Haste, Firststrike, Modular 2, Fabricate 2.
Extension {2}{w}{b}{r} (You may cast this spell for
its extension cost, when you do Mutate it below
another artifact creature you control. The top
creature gets +X/+Y where X is this creatures
power and Y is its toughness. This does not count
as Mutating.)
A.027, Myr of Battle can be your commander.