Polis the Planeshifter

When Polis the Planeshifter enters the battlefield, choose a plane at random from among all planechase planes. Polis the Planeshifter has all abilities of the last chosen plane. (Rolls of the planar die don't affect Polis.)
{W}{U}{B}{R}{G}: Flip a coin. If you win the flip, do Polis the Planeshifter's chaos ensues effect. If you lose the flip, choose a new plane for Polis the Planeshifter.