Dropped 3rd strike?

[achyfuzzball]

I know this is going to sounds like a stupid question but, what constitutes a "dropped 3rd strike"? I know, ball gets by F2 ect, but what if ball hits ground before reaching home plate, batter swings, catcher fields the ball on the bounce? Checked the ASA rule book, but not being very smart, was not very clear to me. Thanks in advance..