>>7484930The Mafex is Eddie, based on earlier appearances. He started out as a somewhat beefier symbiote Spidey, but with a mouth full of sharp teeth. Over time he was drawn more muscular and the mouth got bigger and more monstrous, eventually culminating in Erik Larsen introducing the big slimy tongue.
The reason for Venom and symbiote Spidey looking different is because Peter and Eddie wanted different things from it, and because Peter's personality is at odds with the symbiote.
When Peter got the symbiote thinking it was just a regular suit, he just wanted a replacement after his was damaged on Battleworld. He wasn't after more power, so it became a new suit that enhanced his strength. And Peter's a good person with a strong will, so the suit took longer to bond and start asserting its own personality, never reaching the monstrous levels it was able to with Eddie.
Eddie wanted the means to become stronger and get revenge on Spider-Man for ruining his life, so the symbiote offered him the means to do so, and since they were both angry and out for revenge they were more in sync than Peter and Venom were, so it could be monstrous right off the bat.
