Shorts resort to hiding shares between bid and ask, washtrading (selling shares to themselves from one account to another) in an effort to create a lower pps, boxing the stock using an illegal trading software, using that software to pick up shares on the bid and place those shares instantly on a lowered ask, just to create walls.

The best thing is to outbid their low bid and take away shares from them on the ask (lowering the size of their walls)