strange sellers

If anyone has been watching the on-screen sellers and buyers for RIA, have they noticed any strange selling orders or buying orders that appear, remain for a little while and then dissappear. There was 20odd thousand selling at 40cents and just before close it was gone? They are constantly appearing in teh 40's and dissappearing. At close on the options someone jst jumped in and bought at 19 cents to create a 90% jump in the day. It all seems a bit odd to me?