Apparently it's the Cassowarie, a native of Australia. How dangerous? It can kill you at worst. At best, it'll just break your leg or slice your skin open. Scary. And kind of mean looking.
For me, all birds are deadly. Well, chicken and turkey at least, I've never been brave enough to taste anything else.
On a side note, don't kill the Cassowarie and eat it, it's endangered.