Supergirl exhibits new powers, manifesting sunstone crystals from her body; so far, she only does so while under great stress (for example, when Cassandra Cain tries to kill her). Supergirl's father implants the crystals within his daughter's body to protect her from malevolent beings from the Phantom Zone. The Zone dwellers are released when Jor-El creates the Phantom Zone Projector and exploits the Zone as a prison. Kara's father, believing that Kal-El is a lure to the Zone denizens, instructs Kara to destroy him. More recent comics have cast this plotline as the result of kryptonite poisoning from the kryptonite asteroid in which she was trapped.