I remember in the mod preview that there were creeper dens, and I see in the release that there are treasure chests. How about a really rare find.. is a Creeper UFO? It could be the ultimate vehicle. It could fly around the map and travel into space, and maybe even have lasers to shoot, be able to hover in the air, and maybe other cool alien technologies. Or maybe instead of finding it in a chest you have to shoot one down and take it for yourself? Just some ideas.