Caves of Chrispenbark

When Caves of Chrispenbark enters the battlefield, roll a 20-sided die. If you get 10 or less, return Caves of Chrispenbark to your hand.
{t}: Add {u}, {r}, or {g} to your mana pool.
{t}, {2}: Creatures you control with Firststrike or Doublestrike also have Unblokable and Haste until end of turn.