I saw someone doing this drug and it's really important I find out what it is!

It was a grey dusty looking cube that they burned picked the ash off and put (i think) into a ***, the police arrived for a unrelated reason and they panicked and hid the cube. If anyone could tell me what it was I would be so greatful!!!
youngunicorn youngunicorn
18-21, F
Aug 20, 2014