Dad jokes. So many dad jokes. “Hi, It’s-a-Me Mario, I’m dad! Bwahahaha!”
He takes film and video game ratings super seriously. “It’s rated PG-13. Junior. So either I’m coming with you, or you can wait until you’re 13 to go see it with your friends without me. Don’t you give me that look!”
If you want to date Wendy Koopa, hoooo boy. You better have her home by 9 pm SHARP, young man. And you’d best be showing up at the door in a suit and tie! Business casual, at the very least.
By the same token, if he ever finds out one of his sons treated a lady in an ungentlemanly fashion, there will be hell to pay. He doesn’t believe in corporal punishment, but you better believe that Koopaling is gonna be grounded for weeks. The contradiction this creates with his habit of regularly kidnapping Princess Peach seems lost on him.
On the other hand, if you want to date/hang out with one of his kids, a good way to get on his good side is to play tennis or golf with him (or go-karting). especially if you can put up a respectable showing.
On the other hand, for the love of God, let him win. He is not a good loser.
He goes to every single one of his kids’ sporting events/recitals/fundraisers, and genuinely enjoys every minute of it. He films everything, and rewatches them all constantly in his spare time. Bottom line is that he’s always super supportive of everything his kids do, no matter what. If one of his sons wanted to start taking ballet lessons, you better believe he’d be at every recital, and be just as enthusiastic about it as he would be if it was a football or soccer game.
He’s an extremely active member of the PTA, and always actively participates in school fundraisers. He volunteers regularly, and has mandatory minimum community service hours for all of his minions. He’s extremely popular with other parents, particularly when bake sales are involved. His Koopa Kupcakes always sell out in a flash, no matter how many he makes.
He’s donated so much money to the school that the library, auditorium, and gymnasium are all named after him. They’re seriously considering just renaming the entire school “Koopa Preparatory Academy” and being done with it.
Despite all this, his kids are still very well behaved and studious. While the teachers and administration are understandably reluctant to take any action against them, the Koopalings know that if Bowser catches wind that they were acting up in school and weaseling out of being disciplined by name dropping their dad, he’ll give them a far worse punishment than anything the school could do.
When Bowser paid for the new school gymnasium, he did so on the stipulation that it have easy roof access and a landing pad for his Koopa Clown Car. He doesn’t use it often, saving it for occasions when he wants his visit to carry extra dramatic effect.