A wizard or other caster with a familiar and share spells can cast shadow projection on his familiar, turning it into a shadow that deals 1d6 strength damage and can kill with it.
The spell states that some things that you get from the shadow form and some things you keep.
It is silent on which BAB you use and whether you keep your stats or use the shadow's stats.
My assumption is that you keep your own stuff for everything that is not specifically called out as changing. Is that right?