Hekaton, Storm Giant King

Your commander's colors are {w}{u}{r}{g}.
{t}: Add {w}, {u}, {r}, {g}, or {2} to your mana pool.
When a giant you control deals combat damage
to a player, exile Hekaton, Storm Giant King,
then return him to the battlefield transformed
under his owner's control.
"Long may the Storm King reign!" - Uthor