Proficiency Dice

Proficiency Dice replace your Proficiency Bonus when determining the value modifying an ability check, attack roll, or saving throw. Proficiency Dice do not replace Proficiency Bonus in any other situations.

Did you know monsters and other creatures are also proficienct in things? Well they do! It's not stated blatantly, but it's there. In case you wanted to know, more dangerous monsters tend to be more proficient in being dangerous! Don't think you're so special.

— Stedd Evenwood