Okay, Bellatrix's weapon Starslasher has three special attack forms. Wasp Sting, Hornet Sting, and Bee Sting.

Starslasher (original form/form 1): Used for regular attacks and most magic spells.
Wasp Sting (Form 2): Used for attacks coming down directly on top of an enemy (Head), because of it length. A Deep purple aura emitts from the weapon when using this form.
Hornet Sting (Form 3): Used for attacks under an enemy (Ankles), to throw them off balance (or, worse case scenario, cut their legs off), from its width. A Green aura emitts from the weapon when using this form.
Bee Sting (Form 4): Used For attacks directly in the middle (Heart;stomach) from it cross X-ish form. (two side wings used to balance it when going through mid-air). A Light Yellow aura emitts from the weapon when in this form.
Bellatrix Photo