not a very christian thing to ask for revenge ideas to enact.. tut tut god will be displeased.
however I'll feed the troll for a giggle.
maybe sign up to some forums as him using his email (can't be that hard to work out his password) or something similar and then post some terrorist type stuff online and maybe even talk about buying tickets to turkey with a view to going to syria?
that or just hit and run in a stolen van?
err maybe a small nuclear device?
dirty bomb?
poison his water supply?
lsd in his water supply?
sign him up to as many spam call and email services as possible?
if he drives then the olde poop in the airvents trick and let the gearbox oil out as there is no light for that?
get copies of his reg plates and then go doing some speeding through as many cam's as you can find?
drop a piano from a building as he walks under it?
brake fluid all over his car or bike etc?
landmine in his garden?
bag over the head from behind, closed with a cable tie. rope round a leg and the other end tied to a car?
mains power to something metal he is going to touch?
liquid dog doings in large volume pumped into his house via any way possible. like air brick, open window, letter box etc?
identity theft and run up some big debts, give money to charity?
not many sensible ideas there but maybe some inspiration... for the nasty revenge driven, church going christian.