Engineering term defining any kind of crapppy material / alloy that is not up to the job it's supposed to do.
This includes also the material used plastic parts often used in automotive for knobs and handles that will snap or shatter during normal use.
A superhero movie where the hero is merely there to show off their superpower, rather than doing heroic acts people can actually relate to, they simply show off the cool tricks they can do to the screen. Going off of the saying "not all heroes wear capes" it's called capeshit because only the (metaphorical) cape has been cared about in the production of the movie.