The first one: Glyptodon. It was basically a big armadillo, but the size of a tiny car. The cool thing is that it actually coexisted with humans, as it went extinct 4000 years ago. There's also fossil remains that show damage from man made spears.
Excellent picks, these are some of my favourites too! South America sure had some cool megafauna. I actually did not know that Glyptodon lived alongside and interacted with humans, so I learned something new today, thanks.