“The D20” has 3 charges, it regains 1d4-1 charges at dawn, at any time you may expend 1 charge to re-roll any D20 roll made by you or another creature and choose which result to take. If “The D20” runs out of charges roll a D20, if the result result is a 1, “The D20” will suffer a -3 penalty to all re-rolls