Well this is just disturbing.
Back in 2016, a mother and her daughter were sharing a Java Chip Frappuccino and witness blood stains smeared along side the cup. According to Washington Post, the blood came from one of their baristas.
But here's when it gets interesting, after tracing back to see which worker/barista was making the beverage, Starbucks find nobody bleeding. Looks like their being sued for battery, assualt, emotional distress, and negilgence.
Source via Washington Post