It's like a membrane. A snake will go right through and everything seems fine. But as soon as you pull the snake out, the membrane closes itself back up.
Are you sure you want to mess with this? It could be abiogenesis in action. I smell a Nobel just around the corner!
OTOH, it could start
crawling out of the drains and incorporating all living flesh into its unstoppable blob-like spreading mass. So maybe you should proceed with plan A.