Ghosts what the heck they do?

Don’t be a Steve. Always use Spoiler tags.

Okay for those of us who logged in and just started playing the main game cause they want to finish the story, would it have been too much trouble to tell us what the ghosts do, green ones charge me and give me a green glow, with no visible shield or health loss and red ones sit around shooting me a bit before they charge and give me a glow.

A simple “Hey! these are what the ghosts are all about.” somewhere outside of jumping into the mission, would be nice if they are going to randomly show up in normal game play.

Also when I first logged into sanctuary the only mission I could track was the Halloween one. Though I am sure lots of people already talked about this.