At the start of the game Momma Hogg will say "We should get a casino in the hotel". Go to City Hall. Go to the man with the blonde hair. Select "Build rooms" on the touch screen, then find the casino. Then, go back to the hotel. You will see Tristan Legend (the man who builds rooms in the hotel). When he takes you in the casino, you will talk. There will be a shake. It is an alien. When you go back in the hotel lobby you will see him. Go outside of the hotel. There will be a man who will sell you a water gun to make the alien go away. It costs 250 Simoleons. Buy it and go back to the hotel. Shoot the alien with the water. He will go away.