What synthetic stimulant is sometimes called flaka or gravel?
Alpha-Pyrrolidinopentiothiophenone: α-Pyrrolidinopentiothiophenone (also known as α-PVT) is a synthetic stimulant of the cathinone class that has been sold online as a designer drug. Alpha-Pyrrolidinopentiophenone:  Colloquially it is sometimes called flakka or gravel.
α-Pyrrolidinopentiothiophenone