Elite Arcanist

[Moocow4u2]

So {elite arcanist}, it's ability says I can cast the instant without paying its cost, X is it's converted mana cost. Does that mean if an instant would cost 3 red, 2 blue, 5 rainbow mana I could pay it all in 10 colorless?

[Kagain123]

Correct

[Spikepit]

So {elite arcanist}, it's ability says I can cast the instant without paying its cost, X is it's converted mana cost. Does that mean if an instant would cost 3 red, 2 blue, 5 rainbow mana I could pay it all in 10 colorless?

Correct