What the heck is Andrewsarchus?

Thanks to Walking with Prehistoric Beasts and many peoples' general fondness for and fascination with prehistoric animals, Andrewsarchus is one of the more popular models in our online gift shop. I was thrilled this morning to find a discussion about our current state of knowledge (or lack thereof) on one of the blogs I enjoy reading: Laelaps. I recommend reading this blog post. Brian has included a video clip from Walking with Prehistoric Beasts showing Andrewsarchus hopping and moving about, as well as a photo and a drawing of its skull and some interesting comments.