1. A sex monster or fuckmonster
2. A person with a monstrous sexual appetite.
3. A person with such a gargantuan sexual addiction so that it creates a disastrous lifestyle that can have catastrophic consequences.
4. An unstoppable sex drive. Like a Fuck Machine
5. So focused on sex that they become oblivious to the rest of the world.
Just as Godzilla trashes Tokyo, a Fuckzilla can trash lives.
Like an unstoppable force of nature, a Fuckzilla does what it must right now, regardless of the future.