Kurtis, Myr Manipulator

Creatures you control are artifacts in addition to
their types. When an artifact enters the battlefield
under your control, add {1} to your mana pool.
{w}{u}{b}{r}{g}: Artifacts are indestructible until
end of turn. Activate this ability only if you
control 4 or more artifacts.
"Once Kurtis learned to manipulate mana itself, we
were all at the mercy of his artifact army".
— Jordan, the Just