I feel like I'm the only one who finds Kyurem to be, y'know, actually scary…
It's an ancient frozen monstrosity known to eat humans. Y'know that feeling you get when Ghetsis sends out his Hydreigon? That's the same impression I get from this thing. Wariness. Like this thing is just hollow, and merciless and cold inside.
The creepy jaws don't help matters.
https://www.youtube.com/watch?v=geMt3U2F8Lc