Ragnon, Multitude of Vaults

At the beginning of each player's upkeep and whenever a player casts a spell, roll a six-sided
die. Until end of turn, whenever a permanent is tapped for mana, it produces a color based on the result of the die rolled this way, whereas 1 is {w}, 2 is {u}, 3 is {b}, 4 is {r}, 5 is {g}, and 6 is {c}.
If you would roll a die, you may pay {x} where X
is the number of dice you've rolled this turn. If you do, instead roll two of those dice and ignore one of those results.