Robinhood stock is up 215% this year, but it cooled off in recent weeks.Robinhood Markets (HOOD 1.69%) has arguably been one of the more disruptive names in the stock market during the past several years. Robinhood's innovative platform, which lets investors buy and sell stocks and trade options, popularized the trading of fractional shares and made commission-free trading mainstream.Robinhood's platform gained a lot of popularity during the COVID-19 pandemic's height, and it has been a popular stock to tra ...