Discussion: most iconic boss battle in the series.

I'm currently making a project for the Smash Bros subreddit that involving giving ever series their unique boss battle, but I cannot decide this alone.

I would like to know what would you people choose for this franchise. I would also appreciate if you tell me how would you adapt the battle accurately to Smash.

Since I already see it coming, those who reply "DJ Octavio" have to specify which battle from which game are we talking about, and how would it work in Smash.

That's all for now. Thanks for your time.