The most dangerous animal that escapes from Scamander's briefcase is the Erumpent. It looks like a giant rhino, its hide repels spells, and it can inject deadly fluid into objects with its horn, which makes them explode.
The Silver Screen Society: Every month this tumblr focuses on a different movie, with a variety of artists providing their interpretations. This month their choice is The Fellowship of the Ring, and yikes, this is one frightening image! In the past they've also dedicated a month to 28 Days Later. While this site doesn't specifically target horror movies, it is very cool, and worth a look!