Skull Amulet of Dice

{t}, roll a six-sided die:
If you roll a 1: add {w} to your mana pool.
If you roll a 2: add {u} to your mana pool.
If you roll a 3: add {b} to your mana pool.
If you roll a 4: add {r} to your mana pool.
If you roll a 5: add {g} to your mana pool.
If you roll a 6: add {c} to your mana pool.