The TVTropes Trope Finder is where you can come to ask questions like "Do we have this one?" and "What's the trope about...?" Trying to rediscover a long lost show or other medium but need a little help? Head to Media Finder and try your luck there. Want to propose a new trope? You should be over at You Know, That Thing Where.
Generally Worf Effect sometimes The World's Expert (on Getting Killed)
Edited by jormis29
And Anyone Can Die
We can never truly eradicate the coronavirus, but we can suppress its threat like influenza
Also see Redshirt Army.
Sacrificial Lion when they get some significant character building before suddenly getting killed off in this way.
Say, our protagonists are a squad of New Meat that the A-team has been training, and we as the audience have seen them interacting enough to start deciding that Alpha One is cool, Alpha Three is a jerk, we ship Alpha Five and the Smart Guy and - holy crap did they just kill off alpha squad?
Edited by Scorpion451
Seconding Worf Effect for the "dreaded" effect OP requested.
When the much hyped up A-Team finally comes to save the day, but get brutally slaughtered by the enemy which serves to underscore the deadliness of this enemy and usually instills a sense of dread. Something used with a bunch of shows, most notably Attack on Titan