>>149739213
It was established in the early Venom era how he worked though

A. The first time we saw the symbiote, it was mimicking Spider-Man's aesthetic so we know it does that

B. The first time we saw Venom as a more monstrous visage, it was when it bonded to Eddie Brock and at that point, was still just like a bulky black Spidey with a creepy grin to showcase it was a living organism

C. When Venom/Eddie did quickly become more alien looking and creature-like, it was never really said whether it took that form because it was mirroring how Eddie felt (which was my headcanon as a kid, it looked all crazy because he was) or whether that was just the default look of the "symbiote race" fully revealed

D. Even back then, the symbiote was a shapeshifter, it much more often than today was shown turning into normal clothes on Brock, turning invisible, etc