They look like acorns to me, but with an alien growth.
http://i377.photobucket.com/albums/o...g/IMG_9787.jpg
http://i377.photobucket.com/albums/o...g/IMG_9788.jpg
I found these on a vehicle that visited our premises today.
Apologies for file sizes. New camera and I haven't a clue how to use it.
Yet.
Many thanks
Nick.