What organism is this?

Question

This is something I found growing under my kitchen’s sink. It looks like a growing potato and it’s really hard (tried to pull it down using a hard cardboard but in vain). I think a knife may work but I want to know what this is and if I should be taking any precaution.

I’ve put up a video of it as well here: https://photos.app.goo.gl/JLqJrxeqnboRn9bg8

Answer 1

That looks to me to be non-biological but rather the result of using an expanding foam filler product to fill in gaps, as might occur in the wallboard where a sink is mounted. Here's an example of such a product: