Looks like some one may have possibly fat fingered foam on Poloniex. Led to what seems like about 3x the average daily volume in aggregate across exchanges that coinmarketcap tracks for foam pricing.
Would be interesting to see if there was a group of wallets on Uniswap(v2) bag holding reactionary sells that went through there. That is unless the sell order didn’t originate on Poloniex.
Who knows what happened but could have setup a bagholder with one whale of a position.