Toxin is an antihero in the Marvel Comics universe. He is the third major symbiote which is a living alien organism that bonds with a living organism (esp. human) to sustain.
Carnage is his father while Venom is his grandfather. Venom named Toxin and aspired him to be his partners while Carnage wanted to murder his symbiote spawn as soon as he was nascence but he felt too weak. Toxin found a human host to live with—Patrick Mulligan.
...There is a melancholy result of this bond though—Patrick had to walk out on his wife and child (new born son) without any explanation while his wife was crying hysterically. Because Patrick is devoted to trying to live an honorable life of virtue [he was previously a policeman] Toxin struggles between his symbiote nature of vehement and destructive behavior while attempting to utilize his abilities for good.
There is a six issue Toxin mini-series. He has superior abilties compared to both Venom and Carnage.