Blaccidents come from unknowing use of the camera on a phone, for instance while the phone's in your pocket you take
pictures by mistake, burying the real picture you took and want to find under a pile of all-black mistake pictures, or blaccidents.
Unlike butt dials, blaccidents can
accumulate up to the hundreds without anyone being able to warn against
what you are doing.
Oh crap, you
have to see this awesome thing, here look!! -- oh wait,
no that one's just a blaccident. Oh no, so is this one!!! Where is that picture!!