"maintaining the basic tenants of superhero design"

This one shows up more in movies than on TV, but it still bugs me every time:
The unstoppable badass villain/henchman who spends most of the story laying waste to anyone in their path, but turns into a bumbling, gibbering idiot just in time for the third act (or whenever they go up against a major cast member who isn't…

It's probably hard to aim that thing one handed…