Impulso

You can expend one use of mythic power
to increase any d20 roll you just made by
rolling 1d6 and adding it to the result.
Using this ability is an immediate action
taken after the result of the original roll
is revealed. This can change the outcome
of the roll. The bonus die gained by using
this ability increases to 1d8 at 4th tier, 1d10
at 7th tier, and 1d12 at 10th tier.