pf2e.fyi
From Pathfinder Treasure Vault (Remastered), which isn't enabled.

Fate Shot

ITEM 6
Price 50 gp
Bulk —

Ammunition any

Activate (concentrate)

Fate shot is made of a nickel-steel alloy carved with the smiling face of a comedic player on one side, while the other side holds the frown of a tragic dramatist. When you hit a target with this ammunition, roll a DC 11 flat check. On a success, treat all the damage dice for your attack as though they rolled the average damage +1, rounded up (for example, a fate shot arrow fired from a shortbow would normally deal 1d6, which has an average of 3.5, so you deal 5 damage). This doesn't affect additional damage dice that only happen on a critical hit, such as those added by the deadly trait. On a failure, roll the damage, but your target takes half damage, and you take the remaining amount as mental damage.

Pathfinder Treasure Vault (Remastered)ORC