Reading modern English is one thing, but understanding Shakespeare is an entirely 'different beast'. [=is an entirely different thing; is entirely different]
a story about a mythical/imaginary 'beast' [='creature'] with two heads
a conflict between man and 'beast' [=between human beings and animals]
(..) What is that I hear and smell? Someone I'll soon send to hell. It's time to see if truth they told who said Tywin Lannister shits gold. You beast. You beast. You killed my wife and now you've taken your father's life. No worse child ever stained this land. Curse the day I named you. (..)2016 TvShow: Game of Thrones Title: Blood of My Blood Season: 6 Episode 6