Dirty Fighting (Akshan Passive)

You imbue a ranged weapon you touch with a sinister enchantment. For the spell’s duration, once per turn when an attack made with the weapon successfully hits a creature, the attacker can choose one of the following effects:

1. The weapon fires an additional spectral arrow, dealing force damage equal to half the damage dealt with the weapon (rounded down). The halved damage does not include additional damage that may have been dealth with abilities such as Hunter's Mark.
2. The attacker’s movement speed increases by 15 feet until the end of their turn.