We open at 10.5, get to 11.5 then abruptly reverse and end up at...

We open at 10.5, get to 11.5 then abruptly reverse and end up at 8.5c on huge volume
How the hell do we go up 15% then down ~30% to close -15% on the day after a supposedly good report?

A couple of potential reasons, I hope someone better informed can help here.
1: This is the only time insiders can sell I am guessing, so someone has a reason, maybe the company is bad, maybe they need money etc. Are insider trades pre scheduled with the regulator? Or just they can sell whenever for a certain period after earnings.
2: I missed something really bad in the report and next quarterly forecast, really I can't tell what, or how it explains the jump and then reverse.
3: Shorters? Though I doubt it, the free float isn't that high and that would be illegal

What really pops out is the huge volume, someone(s) trying to get out and there has to be a good reason for it.