Consider the Potion of Giant Size, from Storm King's Thunder (p. 236, Appendix B):
Everything you are carrying and wearing also increases in size for the duration. When rolling damage for weapons enlarged in this manner, roll three times the normal number of dice; for example, an enlarged longsword would deal 3d8 slashing damage (instead of 1d8), or 3d10 slashing damage (instead of 1d10) when used with two hands.
Now consider a weapon such as the Oathbow:
If the attack hits, your sworn enemy takes an extra 3d6 piercing damage.
If a character enlarged by a Potion of Giant Size hits a sworn enemy with an Oathbow, what damage dice do you roll?
- 3d8 + 3d6?
- 3d8 + 9d6?