idle dropped low and blew some smoke..O_o

Ok I was driving along minding my own business, I pulled into a parking lot to talk to a buddy of mine. Well I’m sittin in my car alongside his and all of a sudden the idle drops to like 500rpm I didn’t think much of it and touched the gas pedal abit to bring it back up and it blew a bunch of smoke. The smoke had an oily smell to it as well. After that it seemed ok, and on the drive home everything felt normal. Anyone have any idea what this could be?

Oh and for the Search Nazi’s, yes I did search but I couldn’t find anything quite like my experience.

nobody?

what colour was the smoke?