The Avengers Vol. 1 (1963-1996) #236

Plot

The Amazing Spider-Man wants to join the Avengers! But the web-slinger passed on his first opportunity way back in Amazing Spider-Man Annual 3. Why is he ready to sign up now? Earth's Mightiest Heroes are lukewarm to the idea and brush off the wall-crawler. However, when Spider-Man sees a quinjet departing the mansion, he hitches a ride! After the quinjet lands at Project Pegasus, Captain America, She-Hulk, and Starfox aren't very happy to find their amazing stowaway. But that attitude changes in a heartbeat when the Avengers discover hordes of Lava Men on the loose! Not to mention Blackout, Electro, Moonstone, and the Rhino! It's pandemonium at Project Pegasus! (mycomicshop.com)