Well, I'll be ...

I've been a fan of the Konami cute 'em up Parodius Da! for many years, but until a few minutes ago I didn't know that the game's omake (bonus) stage features a trio of secret bosses--all of which can be seen in the following video:



Of course, my lack of knowledge in this area likely stems from the fact that I absolutely suck at said omake stage.

See also: '10 video games that made my life gayer (#4): Parodius'