Monkey Minions are generic NPCs that are found in every region, including The Future when it still existed. A sub-group of these are called Monkey Skyway Agents and can take the player to different areas within a single region (the only cross-regional trip is from Foster's Home to Camp Kidney). Some of them, such as Boomer Bango and Jibba Jabba, are mission handlers for Mojo Jojo,. They don't give many missions to players who do not have Mojo Jojo as a guide; often times the missions are Nano enhancement missions -- or just very easy. Although Monkey Minions don't give missions often, they are often involved in mission objectives.
It is revealed during Mojo Jojo's nano mission that Spawn Simians are actually corrupted Monkey Minions; their mutation was caused by their eating Fusion bananas. Monkey Minions have an armor set that can be obtained during Guide Missions from Mojo Jojo.