This adjective for a scathing comment or review literally refers to sulfuric acid
[DOC] [TLE] Sulfuric acid | Define Sulfuric acid at Dictionary.com [PAR] Sulfuric acid definition, a clear, colorless to brownish, dense, oily, corrosive, 
water-miscible liquid, H 2 SO 4 , usually produced from sulfur dioxide: used 
chiefly in... [DOC] [TLE] A word a day: Vitriolic Meaning and Usage [PAR] Jul 1, 2009 ... Adjective 1.