9. The Ridiculous Final Form
Many video games will pit players against the antagonist more than once before it's all said and done, and it's incredibly common for the final boss fight to unfold in multiple phases.
Typically, you'll fight a more recognisable, manageable version of the villain before they're transformed into a bigger, badder rendition, usually with some sort of supernatural or cybernetic upgrade.
The textbook example is of course Final Fantasy VII's Sephiroth, who starts out resembling a pretty regular humanoid, before becoming an angelic monstrosity in his final Safer Sephiroth form.
Square Enix loves this cliche in general, really, but it's widely prevalent across video game genres.
Batman: Arkham Asylum infamously saw the Joker transformed into a gigantic, hulking mutation of his former self, while Ganondorf has a habit of beefing-up his form throughout the Zelda franchise, and of course, who can forget Undertale's grotesque Photoshop Flowey?
It's such a completely predictable route for final boss fights to go, and yet as long as the design work is creative enough, it can still be a ton of fun, cliches be-damned.