Rivian Automotive (RIVN -6.12%) stock is parked in a lot fewer portfolios today. Shares of the electric vehicle (EV) upstart plunged on Tuesday morning, extending the decline they endured yesterday.While EV investors who clicked the sell button had their reasons, those who still count Rivian stock among their holdings -- or those interested in buying the stock -- are wondering what to do next. Let's take a look to see what investors' next move should be with regard to Rivian stock.Season that price target w ...