Vivek Ramaswamy's Axovant Sciences announced its Alzheimer's drug intepirdine failed clinical trials, causing the stock to crash 75% in one day from $200 to eventually 40 cents. Ramaswamy had sold $40 million of his personal stake at the peak while hyping the drug in media. The drug had already failed four GlaxoSmithKline trials before Axovant bought it for $5 million, fleecing thousands of retail investors in what critics called a pump-and-dump scheme.