Blackwater

Yesterday I was messing around in the RRC (installing new radio and speakers). After I re-wired the radio, I started the RRC just to make sure the radio turned on and off with the ignition. Since the RRC actually started this time, I let it run for a minute. For whatever reason, I looked to the back of the truck while tapping the gas pedal and noticed it spray black mist from the exhaust. I did it again, but a little more aggressive on the pedal, and it sprayed out black water with a lot of black smoke this time. In fact, it coated my driveway with this stuff.

I shut the RRC off and walked to the back. Stuck my finger in the tail pipe and wiped some of the black watery substance on to my fingers. It has no smell at all (not oil, fuel, coolant, nothing). The water appears to wipe right off but the black carbon looking stuff sticks to the finger.

Any clue what this means??