Why do crypto pumps happen?

Could you elaborate on the phenomenon of "crypto pumps"? It seems that there's a sudden surge in the price of certain cryptocurrencies, often accompanied by a flurry of social media activity and promotional messages. What are the primary drivers behind these pumps? Are they orchestrated by a select few with a vested interest, or are they the result of genuine market demand and speculation? And what are the potential risks and implications for investors who find themselves caught up in the excitement of a crypto pump?