Kurtis, Myr Manipulator

All creatures you control are artifacts in addition
to their other types. If an artifact comes into play
under your control, you may add {1}
If you control at least 4 artifacts, you may pay: {2}{w}{u}{b}{r}{g}. If you do, all artifacts gain indestructible until the end of turn.
"Once Kurtis learned to manipulate mana itself, we
were at the mercy of an artifact army."
—Jordan, the Just