Give me some "holy sh... did that just happen" ideas

[MikkOwl]

Some people seem to misunderstand what this topic is about.

Instructions, from the first post of the topic:

..looking for some ideas to break up the monotony. Things that make you jump out of your seat. Things that immerse you in the game world. These can be based on historical events, or these can be your own ideas, as long as they're rooted in reality.

This means things that happen before the mission, during the mission, or after the mission. Interesting new mission types. Events. Features. These can be one-off events we may try to recreate during the mission, or more general ideas such as "it'd be cool if X did Y when Z".