The Manaflux Monster

Diminish (You may reduce this spell's cost by
discarding cards as you cast it. Each card you discard
while casting this spell pays for {1} or one mana of the
discarded card's color.)

{1}{b}{g}{u}, Reveal a permanent card from your
hand: Manaflux Monster becomes a copy of the
revealed card until end of turn.
Beware every blade of grass and every pebble on your
path, for it takes but a moment to be replaced.