Looking for ways to have fun in your archives? Play Guess that Goo!

Howdy Archival types! Are you bored with arranging and describing? Genealogists driving you bonkers? Well then, gather 'round and let's play another exciting game of "Guess that Goo!" Look closely and see if you can determine what on earth the mysterious, sticky, possibly toxic (but hopefully not since I stuck my finger in it), black substance is.

Ick.