When Bitcoin drops, altcoins usually drop as well. There are a few reasons for this. First, when Bitcoin goes down, it often takes the whole market with it. This is because Bitcoin is the most dominant cryptocurrency, and usually sets the tone for the market.
Second, when Bitcoin goes down, it often means that people are selling off their altcoins to buy Bitcoin. This is because people generally see Bitcoin as being more stable and valuable than altcoins. Finally, when Bitcoin drops, it can often mean that there is a general lack of confidence in the cryptocurrency market as a whole. This can lead to people selling off their altcoins in order to get out of the market altogether.