The cop's (Detective Mulligan's) eyes turned blue in Venom: Let There Be Carnage because he was implanted with a new symbiote, hinted to be the powerful Toxin from Marvel comics, after surviving an attack by Shriek; this was a setup for future movies, showing he was alive but now bonded with a different alien.
In his final scene, actor Stephen Graham shows off the glowing blue eyes of seemingly possessed police officer Pat Mulligan. Mulligan just so happens to share his name with the first host of the Toxin symbiote in Marvel's numerous Venom spinoff comics.
Against all odds, Mulligan survived his assassination attempt after an unknown Symbiote bonded with him. Shortly after being saved, Mulligan's eyes began to glow blue while he whispered the word, "Monsters".
According to the comics, Carnage is Venom's (the Symbiote alien itself, not the typical venom form) son and evolved the ability to bond with his host's red blood cells, creating a stronger bond between symbiote and host. So in the comics, Carnage is red because he's soaked in the blood of his host.
Additionally, due to Symbiote biology, Toxin is stronger than both Venom and Carnage. In the comics, Toxin can crawl on the walls and shoot unlimited webbing because of Venom's past association with Spider-Man.
During a confrontation in a cathedral between the Venom and Carnage symbiotes, Mulligan was apparently killed by Barrison. However, he absorbs a piece of Carnage, which later revives him and causes his eyes to glow blue. Patrick Mulligan appears in Venom: The Last Dance, portrayed again by Stephen Graham.
Venom Settles a Huge Fan Debate: Yes, Symbiote Colors Matter - IMDb. Venom #8 confirms symbiote colors matter, with red symbiotes being stronger than black. Red symbiotes signify a perfect bond with a host, potentially explaining their increased strength.
In the "Venom Inc." storyline, Venom is captured by the Life Foundation and was experimented on. The Life Foundation accidentally pour hydrochloric acid on Venom, giving him a white appearance and new abilities, including intangibility.
Sometime later, Green Goblin abducted Peter Parker and injected him with the Venom symbiote. Green Goblin did this because he thought of his son, Harry Osborn, as a disappointment and thought that because Peter was intelligent he could be the son he never had.
She became a drug dealer, which exposed her to situations that ultimately damaged her sanity; namely, being shot in the head by a police officer, and being put in Cloak's Darkforce, which awakened Shriek's latent mutant abilities. Shriek debuted at the start of the "Maximum Carnage" crossover.
The new symbiote then bonded with Cletus Kasady through a cut on his hand, transforming him into Carnage.
Carnage is a sentient being of pure evil, seen by how moments after the Symbiote was born, he had wreaked havoc in prison during his escape. Carnage also has a deep hatred for his father, Venom, wanting to kill him so that he could be the only Symbiote on the planet and therefore unstoppable.
That same issue also showcases his fully-formed symbiote form when he finally bonds with Officer Mulligan during a fight with his father and grandpappy. During this fight, one thing became abundantly clear: as strong as Venom and Carnage are, Toxin is much, much stronger.
Becoming Venom's Grandson
Weakened by the actual birthing, Carnage was unable to kill the newborn symbiote. Supplanting the symbiote in Patrick Mulligan, a New York City cop, it returned in later days. Venom named the new symbiote Toxin, after himself.
Eddie Brock. David Michelinie would later write the backstory of Eddie Brock as the alien's new host that would become the villain Venom, using the events of Peter David's 1985 "Sin Eater" storyline in The Spectacular Spider-Man as a basis for Brock's origin.
In fact, right after its birth, the symbiote proved to be more adaptive than its father Venom, merging with Kasady's blood to forge a more visceral bond with its host. This also gave its “skin” that distinctive red hue.
In the Marvel universe, symbiotes, in addition to needing a host, feed on adrenaline or phenethylamine. In the human brain there is phenethylamine, a chemical found as a neurotransmitter. So Venom and others symbiote eat heads for feeding.
Knull, the dark god of the symbiotes, is the creator of the first symbiote, Venom, and he waged a brutal war against the celestial beings, using his power to shroud the universe in darkness.
We know for example, in the movie Venom mentions he was bullied on his homeplanet (Klyntar) for being the weakest, and being like a “loser”. Pretty much confirming he is one of or thee weakest symbiote. We know he's definitely weaker than ones like Riot, Carnage, Toxin, etc.
Knull appears in Venom: The Last Dance, portrayed by Andy Serkis. This version is the creator of the Symbiotes and the Xenophages, intended to destroy all life and light in the universe. However, his Symbiotes betrayed him and imprisoned him on his own world.
Trial 4 is a 2020 true crime documentary television series directed by Rémy Burkel.
While the Carnage symbiote is often bonded to Kasady, the symbiote is known to jump around to other hosts. For a time, he bonds to Normie Osborn, Norman Osborn, AKA Green Goblin's grandson. Carnage is psychically linked to the Life Foundation symbiotes through his parent symbiote Venom.
Shriek broke her fall slightly by grabbing onto some curtains, yet upon hitting the ground, she saw the dislodged bell from the tower falling toward her. Before she could let out one final scream, the bell crushed her to death.