I am relatively new to this share investing and trading business...

I am relatively new to this share investing and trading business and would welcome an explanation as to why someone would sell 1 share on the last trade of the day at 1/2 cent less than the price going price.
Is this to try and keep a cap on the share price?
Is it some kind of share price manipulation method?
Is there any logical reason for doing this other than the possible reasons above?
Does this mean that someone / some organisation is now stalking and manipulating HXG shares?
Do company management keep an eye on transaction like this?

POP