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End of twitter post by Elon Musk
He also linked to the Wall Street bets forum, where he's lovingly referred to as Papa Musk.
What was the point of it all?
It's a good question.
For lots of people involved, it was just a laugh.
Some excitement, something to pass the time with - an experiment to see the power of internet communities.
Wall Street commentators have called it a "phenomenon", "insane", and like "nothing [they've] ever seen".
For many, the aim was to make stockbrokers and hedge funds lose money. Popular threads on Reddit include people saying it was payback - taking revenge against the big money companies seen as causing the financial crash in 2008.
Analyst Neil Wilson says some of the traders had a "peculiar vigilante morality".
"They seem hell-bent on taking on Wall Street, they seem to hate hedge funds and threads are peppered with insults about 'boomer' money.
"It's a generational fight, redistributive and all about robbing the rich to give to the millennial 'poor'."
Some people on the forum said they donated their earnings to charity afterwards.
If nothing else, it was a good chance to make some memes.