How would one go about making a feature like the miner hat in the impossible line ios app ?

I've tried anything i could think of and so far to no avail, the only way i get it to be sort of vaguely similar is by using a very expensive way of casting ray in a 360 disc and using the debug.drawline method. I had an attempt at using a spot light but since the only way to get it to cast shadows is to use the deferred lighting rendering path and that is not possible for iOS, its no go. I can't create the mesh at runtime, and i think I can't modify the shape of a 2d texture at runtime either. I tried unsuccessfully with particle too but that might be me being noob since i never used them before. I'm at a loss as how to go forward, any help/ideas would be greatly appreciated.