Used to work in a hospital.

One time a kid in the emergency room was coughing and coughing and coughing. He coughed up this creepy ooze!!

It is an oozy, rubbery mucous cast of the breathing tube network inside of the lungs.

I touched it because I'm a creepy guy :-0 (had to know what it felt like).

Working in a hospital I had the misfortune of accidentally touching many creepy oozes (urine, feces, snot, pus, blood, leeches, etc.), but this was the creepiest because of its alien appearance (a snot alien basically).