Do you think you could describe possible interactions between Sirius and Vernon? :)
man oh man okay. so. sirius has always detested vernon? ever since lily told them that petunia was seeing this walrus of a man who despised magic. so sirius knew right then and there. no one hates on his friends and gets away with it.
so obviously, when lily and james start to get more serious, james finally meets vernon himself. and of course, recounts every single thing back to sirius when he gets home. sirius is livid.
and he never tells anyone, but he transforms into padfoot that night to w r e c k vernon’s garden. lily has her suspicions but she never tells james- she doesn’t want vernon to wake up one night and die of fright when he sees a stag and a dog burrowing holes in his grass
then in the final summer holiday sirius and lily are having their annual lets relax and snooze with our feet up on the sofa, watching tv, eating junk and forgetting about the world (but this time, james is invited too ofc and mary) and there’s a knock on the door, followed by petunia’s screeches of ‘lily why are your freak friends here?’. mary met vernon one time whilst at lily’s (and she’s had to endure a lot of ‘freak’s from petunia), she told sirius what a complete idiot and prejudiced piece of junk vernon was. so of course sirius is curious (and v angry abt how he has treated the three most important people of his life)
so. they’re all sat on the sofa and all share a look of alarm with each other as they hear the door open, petunia’s shrill voice and a very deep voice that’s horrifically posh and rather like a fog horn. sirius cranes his neck to see through the door, almost falls off the sofa and catches vernon gaze as mary and james are having to pull him back up from the floor. vernon just raises an eyebrow at him, turns his nose up and glares. then walks away with petunia.
sirius is already standing up, pushing his shirt sleeves to his elbows ready to fight but they all push him back down and. that night sirius destroys vernon’s rose bush.
the next time they meet is at vernon + petunia’s wedding. of course lily and james are (begrudgingly) invited, so mary and sirius wait by the parking lot to give jily their support. they both came on sirius’s motorbike and when the new mr and mrs dursley leave the church there’s this shiny, fancy black car with white ribbon dressed all over it. of course, the motorbike sticks out like a sore thumb and vernon tuts as they have to pass the bike, talking about how it looks like a piece of rubbish. sirius can’t help but mutter back a rather rude comeback and once again mary has to hold him back before he gives vernon a bloody nose. she calms him down as jily arrive and they all leave.
obviously, lily doesn’t meet petunia much after this. she visits their home on very rare occasions, but when she tells petunia that she’s marrying james lily knows it’ll probably be the last time they meet. sirius tells her they don’t deserve her, that she’s a far better person than they’d ever be, and they spend time talking about siblings and the pain that comes from that.
then it’s october 31st and sirius had actually forgotten all about horrid vernon dursley. but then james and lily are dead and he’s broken beyond repair, and harry is the only thing left of the potter family, of their past, of their legacy. when sirius arrives he sees baby harry there with hagrid and of course gives hagrid his motorbike (he has no use for it, and there are too many memories that remind of him james there. he can’t look at it anymore). he knows harry is going to live with the dursleys. and sirius is apprehensive- he remembers how vernon was and all he can do is pray that he has some sort of mercy on small baby harry.
years later vernon sees a familiar black dog in his garden, and it has those familiar grey eyes of a certain someone who was always hanging around with that potter fellow. he stares at the dog and the dog stares back and vernon just gives him a nod before the dog walks away.
then when sirius meets vernon in the afterlife, after finding out how he treated harry, he gives him that well deserved bloody nose