This is normally the type of thing that would require a pic to do well, since nothing comes to mind for me only knowing the color and presence of spikey projections. I don't really understand what you mean by helix shaped, since that made me immediately think of this:
http://www.gastropods.com/Shell_Images/C-Conus/Callostracum_gracile_3.jpg
but I have a feeling that's not heading in the right direction. So...
Shell: how pointy is this beast, more flat/round or more like a Cerith?
Spikes: flattened, rows, thin, wide, evenly distributed...?
Operculum: knobbly, thick, smooth, flat, any obvious growth pattern like spirals...?