The Flash: DC Comics' Version Of The Chronoball Is Even More Ridiculous
This article contains spoilers for "The Flash"
The DC movie universe's version of the Flash (Ezra Miller) isn't just a pair of quick feet. As his namesake movie reveals, he's also acquired a whole bunch of his comic book counterpart's powers, from vibrating his molecules in order to phase through solid objects to actually time-traveling. That latter aspect of Barry Allen's powers is the driving force of "The Flash's" central story, as an encounter with a mysterious figure sends Barry into an alternate timeline where Michael Keaton's Batman is the only superhero — at least, at the point Barry arrives — and General Zod (Michael Shannon) is free to rampage as he wishes.
The film visits the time-traveling energy sphere that Barry dubs "chronoball" multiple times, and the final showdown takes place inside it, as well. It's a unique take on the subject of traversing time and alternate universes — and it's not without its flaws. Not only is the concept of the chronoball rather strange, but "The Flash's" famously bad CGI can render the time-traveling experience somewhat less than immersive.
Still, things could be worse. In the comics, the Flash's time-traveling device of choice is the Cosmic Treadmill –a much more ridiculous contraption that, weirdly enough, is exactly what it says on the tin.
The Flash isn't afraid to get ridiculous, but the Cosmic Treadmill would have been too much
The Cosmic Treadmill is a custom device that's basically a fancy-looking gym treadmill — only, the Flash and people with similar abilities can use it to travel in time. An integral part of the Flash's comic book adventures, the machine is nevertheless a very, very comic book-y concept. As such, even in a movie that features a literal baby shower, the Cosmic Treadmill would probably have stood out ... especially since "The Flash's" plot doesn't really have room for Barry to require an external contraption for time-travelling, as it relies heavily on his ability to do so without external help.
Apart from this, there are likely two reasons why "The Flash" wanted to avoid using the Cosmic Treadmill as its time-traveling Macguffin of choice. For one, there's the matter of visuals, as a fairly regular-looking treadmill is a far less impressive time-traveling vehicle than, say, a "Back to the Future"-style DeLorean or a "Doctor Who" TARDIS. Of course, there's also the fact that the Arrowverse version of the Flash (Grant Gustin) actually uses a version of the Cosmic Treadmill for testing his super-speed ... and the DC movie universe loves to avoid any undue connections to the Arrowverse and its long march to cultural irrelevance.