The anticipated impact on Hershey's stock price in the short term is negative due to the dual pressures of rising cocoa prices and the emergence of Feastables as a strong competitor. These factors are likely to affect Hershey's profit margins and market share, as indicated by the company's cautious outlook and the market's reaction to similar challenges in the past. The decline in Hershey's stock price over the last year further underscores the market's concern about these challenges.