Prism Mage

Whenever you cast a multicolored spell, choose one at random - Gain 4 life; or draw a card, then discard a card; or each player discards a card; or deal 1 damage to all creatures; or put a land card from your hand into play tapped; or scry 3.
{5}: Add {w}{u}{b}{r}{g} to your mana pool.