Venom in the 1994 Spider-Man Cartoon
Venom made his first appearance early on in the 1994 Spider-Man Cartoon. Episode 8 highlights the symbiote's arrival to Earth, episode 9 shows us the epic scene where it bonds with Eddie Brock, and episode 10 features Venom in all his glory. If you have never seen these before, take a look. I think this series is the best comic book cartoon ever made.
Episode 8 - The Alien Costume Pt I
Episode 9 - The Alien Costume Pt II
Episode 10 - The Alien Costume Pt III