Don't touch it! It's cat pi$$.

 

I would have thought it was carbony water too, but it didn't come from the mufflers. I looked in the trunk and couldn't find anything. Strange.

 

There is only one sure way to find out what it is. Scoop up as much as you can and send it to a oil lab. Shouldn't cost more that 30 bucks or so but you will know for sure.

 

The forth pic looks like it could be your fuel vapor canister(system) and the fifth could be the trunk.

 

Could it be the vent for the gas tank? Maybe the filter has a build up.

 

That's what I initially posted, then edited after I saw it coming from that plug on the underside of the body.

 

It looks like excess fluid from the evaporative emissions system. It's found in the "box" under the spare tire recess below the body. It could be a leak in the system.

 

Get some newspaper and "housebreak" that pony

 

The plug shown in your last pic is a drain plug for the spare wheel well. It's wet appearance indicates that water had accumulated in the spare wheel well, and was dripping out thru the plug's opening. Considering that the liquid on your garage floor had a dirty brown appearance, then the source of the water may be from wet roads. The following is my reasoning behind this possibility.

After noticing one day that condensation had formed on the interior of my S197's rear window, I inspected the trunk for water. The trunk's cloth cover was dry. However, a lot of water had collected in the spare wheel well. But the water contained a lot of dirt, which seemed strange. When I pulled everything out of the trunk, I noticed that the bottom left side of the plywood under the cloth covering was wet, and there were traces of water leading back to the plastic cover in the left side of the trunk. After removing the cover, I found dirty water laying in a trough of the quarter panel. After drying it and cleaning out the dirt, I closed the trunk lid and sprayed the trunk and window seams with high pressure hose water. No evidence of water anywhere in the trunk, including the spare wheel well. So I reasoned if the water is not entering the trunk from above, then it may be entering from below. So this time I sprayed water up into the driver's side rear tire wheel well. Sure enough, the quarter panel's trough filled up again. After drying it out, I selectively sprayed different spots of the wheel well area, and checked for water after spraying each one. The only time water collected in the trough was when I sprayed the junction where the gas filler tube passes thru the quarter panel on the underside of the car. I dried out the trough, jacked up the car, removed the tire, sealed the area with duct seal, and sprayed again. This time the trough stayed bone dry.
Mystery solved. The cause of the problem was the driver's side rear tire splashed dirty water onto the poorly sealed gas tube/quarter panel junction when road surfaces were wet. The water then seeped thru, flowed down the interior wall of the quarter panel, and collected in its trough. Then, when the trough filled up(or when the car accelerated or went up an incline), the water spilled out and flowed undetected beneath the trunk cloth cover's plywood into the spare wheel well. BTW, both the trough and spare wheel well have since remained dry.

 

Interesting, I will look into that further in a few days when it gets a little warmer outside. Thanks for the detailed post!

 

You're welcome.
You may find that both the spare wheel well and quarter panel trough are dry if you haven't recently traveled on any wet roads. But if any dirt and grit are present in either area, then there's a good chance that you car has the same problem that mine had.