It is a spray on coating used for giving a surface a rubber coat supposed to be used to make a rubber handle on a tool or something of that nature.
It is somewhat easily removed, or at least far easier than paint.
Many people use it to "paint" certain parts of their cars (wheels, spoilers, etc.) instead of something more permanent in case they do not like it and can remove it.
---------- Post added at 10:14 PM ---------- Previous post was at 10:13 PM ----------
But there has been so many threads about it and how wonderful many people find it to be that many of us on here have simply turned it into a joke