A Chaotic Symbiote Bonded To Natasha Romanoff/Black Widow

The main universe in this fanfic is the MCU otherwise known as Earth-199999. But MC and his host, Natasha Romanoff AKA Black Widow, will travel to different universes because MC's way of development is by eating other Symbiotes and gaining all of their abilities and powers. - What happens when someone dies, is it the end? Do they just cease to exist? Do they end up in heaven or hell? Do they get reincarnated? Or does something else happen? Well, for our protagonist, a just-barely-out-of-his-teens young man named Ali Lightborne, it's the third option! When he died in his world of nothing but ordinariness, a R.O.B casually picks someone up, and it happened to be him! One of his wishes was to have his soul be separated into as many pieces he wanted, and sent to different universes, with their own wishes! And this Ali, asked to be an alien. What did he want to be? A Kryptonian? A Saiyan? No, a Klyntar! Or famously known as a Symbiote! His host? It's Natasha Romanoff AKA Black Widow AKA mommy dommy!