So a few weeks ago my dad gave me some of his old books, one of them is a Super Mario Bros 2 coloring/activity book. On the first page, I see this.
Keep in mind that Nintendo doesn't even really care about canon at all when it comes to the Mario franchise, so nothing can really still be canon or retconned outside of the original media. It's really more about your personal headcanons and preference than anything.What does everyone think of the Mushroom King? Do you think we should still consider him a canon part of the Marioverse, or should we consider him to be virtually retconned by Nintendo? I've heard arguments for both.
Personally, I think he's been retconned. If Nintendo wanted him to remain a part of the Marioverse, then he would be included in or at least mentioned by modern Mario games.