This guy is only playing with you and the markets. It's all fun for him, he's just trolling.
He was playing with real intention of making money.
This tweet does not only give growth to DOGE but it has also affected other altcoins as Elon is the new hype of the market now.
We don't know if its over or there will be tweet to come soon, but he is really the hero for bullish people since his tweet can move the market resulting into millions or billions in price movement in overall.