The scariest might be the one about the lost children's spirits. There are tales of children who got lost in the thick jungles of Pulau Ubin and never found their way out alive. Their spirits are said to roam around, and some have heard the faint sounds of children crying or laughing in the middle of the night. It sends chills down your spine just thinking about it.
There are stories of phantom soldiers on Pulau Ubin. It is said that during a war (although not many details are clear which war specifically), soldiers lost their lives on the island. Some visitors have reported hearing the sound of marching boots and faint battle cries as if the ghosts of those soldiers are still reliving their last moments. This gives an eerie feeling, especially in the more secluded parts of the island.
Well, without further details, it's difficult to say precisely. However, perhaps it's a story where the German girl found herself in Pulau Ubin for a particular reason. Maybe she was traveling, or there was some family connection. It could involve her interactions with the local people, the natural beauty of the island, or a series of events that are specific to that location and her as a German individual.