It's based on a standard 3d6+skill vs target number mechanic used by several games, but in thinking of ideas for special abilities or unique situations, I came up with this idea (NOTE: opposite sides of d6 always sum to 7):

It's called "the flip." When directed, you flip one of the dice to its opposite side. For example, you might have an ability that allows you to flip any one die when you attack a wounded foe. Let's say you have an attack value of +4 and you need to roll 15 or higher to land a blow. You roll 4, 4, 1, which would normally be a total of 9. Even when adding your +4 attack skill, the total of 13 still fails. BUT, you've got a special ability that allows you to flip the 1 to a 6, giving you a final result of 18.

You could also have something more specific, such as an ability or situation where you can flip only dice that result in a 3 (flipping it would result in a 4). Maybe an ability that, at first, allows you to flip a single result of 3, then improve it to include 3 and 2, etc.

I'm not thinking of it as a replacement for modifiers or increased/decreased target numbers, but for a handful of special abilities where it lends a less certain - but potentially more dramatic - outcome.

Thoughts?