Nothing, doubt they speak English and doubt there is benefit to them hanging out on this podunk backwards little planet. I would motion like a space-ship crashing into the planet, then have them take me to their ship. I would try to get their ship running so they leave and do not attract a bunch of agents and get their ship hijacked, impounded or get deported. If I am no help fixing the ship Ill try to hide it. If they won't leave I will have them sit with me to watch Independance Day and if they think its a documentary I will not correct them.