Lux, the Code Cracker

Whenever an artifact enters the battlefield under
your control, choose a color. Lux and artifacts
you control gain protection from that color until
end of turn.
{4}{u/r}, {t}: You get {e}, then choose target tapped
artifact you don't control. You may pay an
amount of {e} equal to its converted mana cost.
If you do, exile it, then return it to the battlefield
under your control and draw a card.