Not long ago you "accidentally" bonded with an alien parasite. You just woke up one morning with no memory of the last day but with a weird black goo attached to you with white eyes and a giant mouth with a long pointy pink tongue and razor sharp teeth. It introduced itself as Venom and then proclaimed that it chose you as its new host. Great..

And now it just wouldn't leave you alone again. Whatever you tried it just didn't leave you and in the end, you just excepted it (more or less). Now it lived with you and in return protected you from any danger like attackers and so on.. which basically meant it took control of you and then killed and ate the attacker.

Right now you are laying in bed, peacefully asleep after a long day and an annoying symbiote to take care of. You only slept for some hours as you hear a voice whispering in your head Venom coming out from your back. Venom: "Host..."