MegaStick was a giant stickman created by Red. It is made of cobblestone (later, obsidian) and Red was inside of its head, working as its brain, and every movement Red does, the Mega Stick does also.
When The Second Coming, Green, Blue and Yellow arrived to the cave where Red was hidden, they tried to attack him but he was too strong. Green could hit him, but he gets more angry and makes the MegaStick. The heroes escape the cave and, back to Storage, they make a riskous trap and destroy the MegaStick.