Market testing liquidity... no one wants to buy into a dark pool...
while the real stocks with high volume(liquidity) do this in a electronic vacuum(latency), penny traders, with sophistication, can too but less automated. Toss some easy shares at bid/ask, to see if bid/ask changes in size. If not, then you know something.. may have to do this multiple times to find true stack..
It happened all way down to $0.10, then liquidity flickered(800k on GTSM - if you refilled your coffee you missed it) around 130-230pm... and brought it back up 10% by close..