New idea for a new enemy, ghost.
Ok, heres how it goes. You know when you spawn in tribes, you are slightly transparent for like a second. You can see this when a bot spawns, if you need to know what I am talking about.
Well, if possible, is there a way to set transparency on an entity in the game?
You can make a skin, most likely white, and have a set transparency on it, and it would look like a ghost.
In fact, now that I think about this, you can do a number of things with that effect. How about make a player model that is in the shape of a glass pane window? it would only be comprised of 6 polygons (it can be a player model) and you can set that transparency thing on it, and make it an NPC. Then, you can place it in a spot on the side of a building, and blammo! Window!