Micronauts

The Micronauts series is about a team of alien space explorers who, while chasing the evil Baron Karza, end up on Earth where they shrink to the size of action figures, forcing them to team up with a human teenager, Cameron Ruck, to fight evil and navigate their new miniature world. It originated from a popular Mego toy line, leading to Marvel comics and animated series that expanded the lore of these tiny heroes on a big planet.