An issue I was faced with during the Bubble Witch Saga 3 project was rebuilding the tentacles and I messed with a couple of different methods to do this, but this is as clean as I have it now. You can simplify this to create the center curve just with the VOP, using a for each you can check the max sample depth and have the point moved to the max depth - though so far I haven't got that to work consistently, so gonna keep digging into that and I'll update the file if/when I solve that. :)
Scene file: www.goo.gl/Jq2DWb