That's King Knight from Shovel Knight. He has his own campaign and does the Wario shoulder bash as his main attack.
The devs also had this quote, "There’s obvious similarities to Wario, with the shoulder tackle. King Knight has a shoulder bash...
I don't think I can pick one to be honest. Breath of the Wild or Tears of the Kingdom would be up there, as would Wario Land 4... but so would Mario Odyssey, DK Bananza and numerous others.
Lol the idea of using Rudy as a Giant Baby Bowser replacement is great.
Would probably look better if his feet weren't visible though, since it'd make him look a lot bigger and more akin to the Yoshi's Island version.