An obscure topic amongst Silent Hill fan bases is how the Otherworld comes in many different ways. I've always found the Otherworld transitions of Silent Hill, and how they occur, to be some of the most fascinating and haunting moments.
In Silent Hill 3, Heather would recieve a headache, usually followed by blood/veins soaking the walls and converting it to the Otherworld.
In Silent Hill: Shattered Memories, an ice would spread over and incase everything in a very thick layer of frosty hell.
In Silent Hill: Origins, a mirror would bring about static and transport Travis to the other side.
In the Silent Hill films, a siren would signal the world going dark, followed by the world peeling and melting away in a spectacular display of visual effects.
So let's hear it, how would YOUR Otherworld come about? What would signal it? What would trigger it? Would darkness come, or would it just happen? What kind of transition would send you back to the Fog World?
For me, a siren would go off, and the sky would turn a sinister, dark red color. Any regular-looking people around would contort into crazy-looking entities. The walls would begin to burn away like a piece of paper, and monsters would come out of their hiding spots.