Just encountered the dragon a few minuts ago but I had a long walk since. If I remember correctly : first, go upstairs (or upbean). Go to the elephant's boat. Always go foward, until you're under the Rabbit's cup of tea. Next, when the boat is stoped, look right and leave the boat. Go to the end of the corridor, and open the dragon's room.

You can also meet the dragon by opening one of the drawers in Rabbit's dresser, then clicking the portrait of the dragon. Or, at the start of the game, open the manhole, go up the beanstalk, watch the dragon fly in and teleport indoors, then go around to the back of the castle to the pool, and turn around and go down the ladder in the ground.

the alien, go outside where the volcano fires, but load the scene with nothing touched (dont fire the volcano) and click on the planet in the upper right. The alien comes down in the UFO