It allows its preferred host to perform cosmic pyrokinesis, as it allows Lady Phoenix from 1,000,000 BC Avengers to perform preternatural flames that can melt supernovas. As for Jean Grey, it allows her to perform cosmic pyrokinesis strong enough to easily defeat Terrax, as she is in complete control of her own cosmic fire that after Terrax submits to his defeat, the fire dissipates at her will leaving him charred. She also does the cosmic fire blast to counter Galactus, as he is quickly engulfed in her cosmic flames before he counters her. In some conditions, even just a bit of cosmic fire can easily burn anything it comes into contact, as when it possesses young Jean Grey the medics tried to put oxygen equipment on her yet she unconsciously melt the equipment. When she is accidentally on fire, the medics are also having hard times to put out the cosmic fire.