What is this black stuff dripping off of the grim reaper? (photo)

"LaBlue0314;848703" wrote:
While at the gym, the grim reaper showed himself again. This time he decided to get something to drink, and while he was sitting at the booth, this black stuff was dripping on the floor. Eventually the back stuff did go away on it's own, and there was an option to mop it up, but decided to just leave the mysterious stuff alone. What is this?
https://scontent-dfw1-1.xx.fbcdn.net/hphotos-xtf1/t31.0-8/11845207_499373853546248_715282701343180527_o.jpg