well time perfectly orchestrated pump and dump. Weak hands fold easily in these environments, as can be seen by the chaotic posting on this forum. These guys know what they are doing and made a ton of cash.
BTW none of this is good for BTC moving forward, as it scares off mainstream participants. they have been burned many many times by wall st, and the idea that BTC was something different in starting to fade away.
If they stuck with bitcoin thus far they don't have a problem. BTC maximalists told them to dump BCH in August and use the proceeds to buy BTC. Anyone who did doubled their $900 to $1800.
BCH holders on the other hand are waking up underwater to a halved price and massive sell walls. If it continues to go that way all it will do is ensure no one ever gets forked over again.