i found a strange organic material.?

I found it on the side of my house. I have never seen something like this. Right away I made the assumption it was a type of mushroom. As I poked it with a stick it had the characteristics of a mushroom, with the slits found on the bottom. But as I picked at it, the inside was gooey, like a brownie mix or black oil product. I wondered if it was flammable, so I started to burn it with a lighter, and after 15-20 seconds of lighting it, it became a solid. I pushed it down to see if the inside was liquid still, and it had turned fully solid. What is this, and what kind of liquid turns solid by heat?