I was watching as it was happening. Times like that I wish I held my coins on the exchange so I could sell them high and buy when they are low. I don't have a ton of bitcoin but I have enough where I could have earned a nice little chunk of change and re-invest to get a little more bitcoin. I know it isnt good to keep your bitcoin on the exchange but darn it this time it would have been nice to have them there. By the time it would have taken me to transfer from my Ledger to GDAX and have it confirmed it would have already dumped back down.
Actually thinking of throwing them onto the exchange now in case it happens again. (I doubt it will though and if it did spike back up to 19k knowing my luck I would sell it to make some profit and it wouldnt go back down it would keep going up) I'll most likely keep it in my ledger.
It was definitely was crazy to watch though. One second I checked it was at 7800 I checked again 2 minutes later it was at 8400 checked again a minute later it was up to 9200. bitcoin amazes me still.