[Death by Mirrors]

Meet Lieutenant Dorotsech. Or Durotsech. Whatever. Doesn't really matter, because that moment you see him appear on screen, you already know he's not going to survive the episode.
That random redshirt has been beamed down on a seemingly peaceful desert planet to collect scientific data. And why not, his credentials are superb. Fresh from Starfleet Academy, appointed cadet of the month. It's not like he has a big sign taped on his back which reads "expendable".
And yet, ten minutes in he's eaten by a wookie. Oh my!
We never saw it coming.