Marvel Secret Wars were action figures produced by Mattel during the mid-80's.
The line included Captain America, Wolverine, Spider-Man, and about a dozen others. All the toys were colorful, and had a secret that could be revealed with the character's shields and certain vehicles.
Mattel produced the toy line in order to compete with the Super Powers action figure toy line from Kenner. I had only a few while I was young, but I loved them. I even tried to swindle a few from an elderly neighbor woman, who kept some for her grandchildren to play with when they came to visit.
Now, I'm still crazy for them. my kids play with my old ones; I buy and keep my best examples in a glass case!