For as long as Hollywood has made movies, audiences have been fascinated by the seedy underbelly of crime and the desperate people drawn into its orbit. Films like Dog Day Afternoon, Goodfellas, Pulp Fiction, and even the early works of the Coen Brothers center around the all-too-human characters at the center of larger-than-life criminal escapades.

That kind of down-to-Earth storytelling was a surefire way to reach critical and commercial success, but in the age of superheroes, those sorts of releases getting mainstream attention is much less likely than it used to be. Action star Frank Grillo, who’s played more than his fair share of on-screen criminals, knows this all too well.

For thousands of years, humans have studied animals’ bodies to better understand our own. But using other animals as a proxy for humans is far from perfect. There are ethical issues for one, and they are never a perfect analog to the intricacies of the human body. In fact, when it comes to studying drugs, animal testing can lead to costly, time-consuming failures.

Nowadays, tech breakthroughs offer researchers new methods of modeling how the human body might react to cutting-edge treatments. And last December, a new U.S. law made it clear that these novel technologies are an option for testing drugs before moving on to human trials. Does that mean this is the end of animal testing?

15 years after Iron Man found out about the "Avengers Initiative," Inverse is ranking every single post-credits scene in the Marvel Cinematic Universe. Help us out by scoring them all on a scale of 1 to 5.