I remember seeing tf2 have a feature called "Sprays" where you take a picture from a file, put it in a folder, press a button when you're up against a wall, and it shows up there for everyone to see. I think it would be interesting for certain scenarios like a granger heading to the human base, and outside the entrance there's a little pick of a granger with two X's where his eyes are saying "Battlegrangers will die beyond this point".
Think that this is a so-so idea?