Few months ago, near the junction of Minden and Holland Roads I heard this very very loud roar, like a big cat (as in tiger / lion / cheetah). But no one else in my group heard it. It came from behind and roar in front of me, around 1m away. Of cos theres nothing there.

My friend said it might be a demon. A few minutes ago before the roaring, I was passing by this huge clump of thick bushes when something drew my eyes into it, which I can't describe. I suppose that's where the demon was residing.
Now, from Bintan. In August, I went there with my school and stayed at Bintan Lagoon Resort, which was by the sea. At night, me and my friends went to the beach for a stroll and to catch the stars. Then, I saw a light fly across the beach, and shortly after my friend suggested we turn back to our rooms. Then as we were walking back, most of us felt this strong feeling of being followed. I sensed it as a black shadow standing on the beach.
Others are like hearing screams when the person beside me heard nothing...