Curate, connect, and discover
instead of going on a murderous rampage, jason decides that the best way to get revenge is to be petty. he puts up an ad saying he's looking for a new mentor, making up a 1 star review for batman saying "he let me die. would not reccommend"
phantom, famous veteran hero and notoriously known for rejecting every offer to join the justice league he's ever received, applies for the position. they proceed to terrorise the jl together.
(danny doesn't kill the joker but he drops him in a cell in walker's prison, which means he's as good as dead.)
(to make this even funnier, other sidekicks slowly start applying to work with phantom. i'm thinking conner kent and roy harper but it could be others)
(danny doesn't hate heroes but he doesn't trust their work with the government. he'll lend a hand if there's an apocalyptic threat but he's marked by the jl as a last resort, both because he's crazy powerful, not a team player and because he'll spend half the time pranking the flash since it amuses clockwork)