If you would roll a die, instead roll two of those dice and ignore one of those results.
The ignored roll never happened as far as any other effect is concerned. For example, an ability that triggers â€œwhenever you roll a dieâ€ wonâ€™t trigger for the ignored roll.
Krarkâ€™s Other Thumb works with any die youâ€™re instructed or allowed to roll.
Krarkâ€™s Other Thumb applies to rerolls as well.
If you are instructed to roll multiple dice, roll two for each one and choose which one counts.
If the die roll includes a physical component, such as Olâ€™ Buzzbark caring where the dice land, roll two dice for each one you would roll. You may need to use colored dice to keep each pair of dice clear so you can ignore one roll from each pair.