Alley Hunter is a 4 star Bow obtained from Weapon Event Wish in Genshin Impact.
Oppidan Ambush
While the character equipped with this weapon is in the party but not on the field, their DMG increases by 2/2.5/3/3.5/4% every second up to a max of 20/25/30/35/40%. When the character is on the field for more than 4s, the aforementioned DMG buff decreases by 4/5/6/7/8% per second until it reaches 0%.