Nobody warned the other muscle cars. Dodge showed up with 707 horsepower, a supercharger whine that resets your heartbeat, and one simple question for every rival on the road: are you still sure you want to race? More than 1.4 million people have watched Autotrader put the Challenger SRT Hellcat through its paces — and almost none of them expected the real question that comes next: is this actually the last great American muscle car?