10 Most Powerful Beings Venom Has Defeated
4. Ms. Marvel - Siege

You're probably wondering how exactly Venom managed to get off a win against Carol Goddamn Danvers of all people. I mean, yeah, Venom is tough, but even when she was Ms. Marvel, Carol was anything but a pushover.
Well the answer is that it didn't... but also did. Let's explain.
During the event comic Siege, Ms. Marvel and Spider-Man are intercepted by Venom, currently inhabiting the body of Mac Gargan, the former Scorpion. Ms. Marvel, not having the time for Gargan's shenanigans, shoves her hand into Venom's chest and rips Gargan out of him. Because Carol Danvers is awesome, that's why.
She certainly impressed the symbiote with that display, seeing as the symbiote then proceeds to pounce on her, taking over her body and becoming She Venom. Not the most creative name in the world, but hey, Venom can fly and shoot space lasers now, so I doubt they care.