Wow. I mean. Wow.
It's a device that Google puts out you plug into your TV's HDMI port. In elementary terms it turns any TV into a smart TV. I use one of mine to stream games, like today's, when I'm outside of the house. I have another I use to mirror windows from my laptop. I have a monitor daisy chained to my laptop and can cast to another as well. Or, just flip that second screen to a TV show. Your browser has the option to "cast," hence Chromecast. They have over 2000 apps available now.
When I first got mine I counted over 700 channels after downloading a few free TV apps.
In this thread I'm talking about the ability to download a browser and pull up different sites off the Internet. Here, pirated movies and TV shows you normally would have to dodge ads with.
In a sense I guess it's in the same family as a Fire stick? I've never had one so I can't answer that. I don't subscribe to sites like HBO Max, Apple, or MGM+ but I watch their shows.