Tom Hardy's son Louis Thomas Hardy is a fan of Venom, and Hardy took the role to please him: "I wanted to do something my son could watch. So I did something where I bite people's heads off." Louis also guided his father on how to appropriately portray Brock/Venom, since Hardy didn't know the character very well.
(at around 44 mins) The restaurant scene was shot once with the live lobsters and once with the fake lobsters. The lobster that Tom Hardy bites into was actually candy shell-coated marshmallow filling with chocolate syrup. The glass tank wasn't exactly designed to support the weight of the ripped actor, "but Tom said, 'Yeah, you guys got to figure this out, but Eddie's going in the tank,' " says Fleischer. And so quickly the crew built a water tank that could also support the star. The resulting scene was shot twice first with real lobsters, and then with fake ones.
Tom Hardy recorded his lines for the Venom symbiote during pre-production, and they were played back to the actor through an earpiece on set during scenes where Brock and the symbiote talk to each other.
(at around 1h 30 mins) The Venom symbiote recommends chocolate. According to the 1995 miniseries "Venom: The Hunger", symbiotes need a chemical called phenethylamine which is available in brains, and chocolate.
Besides portraying Eddie Brock, Tom Hardy also provided the voice and physical stand-in for several scenes of Venom.