The reason that the symbiote can make webbing is because it emulated Spider-man's thought pattern on the Battleworld during Secret Wars. When everyone was getting their new costumes, I beleive after being resurrected by Colossus, the only survivor after Dr. Doom killed them all with a 'bolt out of the blue', they went to a machine that read their thoughts and created a costume accordingly. Spider-man went to the wrong machine, and the symbiote that it spawned emulated Spider-Woman's costume of the Avengers (because Peter kept checking her out). As for the webbing, Peter's web shooters were damaged in the attack and weren't working. It seems that when the symbiote was spawned out of the machine, it knew of Spider-man's reliance on webbing by knowing his throught processes. But the fact of the matter is, the symbiote doesn't really have the ability to generate 'webbing'. Rather, using a very small amount of its own essence, it creates a substance that emulates webbing. The symbiote's 'web' is actually stronger than Spider-man's artificial web fluid, making it far more effective. Its ability to process the webbing IS limited...over time it can wear itself out because the webbing is created from its own being. The symbiote uses this method to get around easily and websling just like its former buddy, Spider-man. The reason that Carnage and the other spawn of Venom cannot use webbing is because they don't need to. Carnage and the rest of Venom's spawn have the ability to stretch their forms out, effectively managing to get around via their own elongated bodies. This is more effective than Venom's web-generating because it doesn't wear them out like the webbing could eventually wear out Venom. Although Venom has the same ability to slither and move his symbiotic body in any way he wants, it isn't as effective as Carnage's ability to use his body to get around. As of current times, Marvel is butchering alot of the classic characters, especially Venom. They're changing around everything about him practically undoing everything we've come to know about the symbiote, so don't be surprised if, despite this answer being based on previous Venom information, suddenly becomes wrong within the next year when they change Venom even further.

toxin son of carnage can make webbing so I think he breaks that last trend Alter ego Patrick Mulligan Team affiliations NYPD Notable aliases Pat, Paddy, Larry, Son of Carnage Abilities Superhuman strength, speed, agility and durability Unlimited symbiotic "webbing" Ability to sense and track anyone Ability to form blades and projectiles from symbiotic costume Ability to stick to any