|Next Phase||Metal Overlord|
Metal Madness is a transformation of Metal Sonic, who's the main antagonist, and the penultimate boss of Sonic Heroes. He makes his appearance in the game's Last Story. Using the information he's collected from the four teams, Metal Sonic was able to transform into this form. This boss battle is fought, using Team Rose, Team Chaotix, and Team Dark.
This boss battle is split into three stages, one for Team Rose, Team Chaotix, and Team Dark. There are three platforms surrounding Metal Madness. Team Rose battles Metal Madness on the right platform, Team Chaotix on the left platform, and finally Team Dark on the front platform.
Each team must attack Metal Madness weakpoint, which is indicated by the colors: red, blue, or yellow. Blue indicates that you can't attack in Speed formation, yellow indicates that you can't attack in Flight formation, and red indicates that you can't attack in Power formation.
 Team Rose
Team Rose is the first team to battle this boss, and his weakpoint color remains blue, therefore you must use Big the Cat(Power) or Cream(Flight) to attack the boss. On their platform are rings and two Wooden Crates, each containing a Team Blast capsule. Metal Madness has attacks, such as a tail swip and a flamethrower, which must be jumped over. The creature will also launch missiles that will sprout spike formations, which Team Rose must avoid. After, draining his health to zero, Team Rose's portion will be complete.
 Team Chaotix
Team Chaotix is the second team to take on Metal Madness, and the creature's weakpoint is either red or yellow, so the players must attack accordingly. On their platform are rings and a cannon. Go inside of the cannon with a Speed character to be sent to a balloon, which holds a Blue Power Core. Going in the cannon with a Flying character leads to a balloon with a Yellow Power Core. Going in with a Power character allows you to aim towards two other balloons, which leads to a Blue and Yellow Power Core. Metal Madness has an additional attack in which he launches a missiles, which will form into crystal cages and trap the player if they are within range. After draining his health, Team Chaotix's portion will be complete.
 Team Dark
Team Dark is the final team to take on Metal Madness, and the creature's weakpoint will change between all 3 colors, so the players must choose the correct formation to attack him. On their platform holds 3 Wooden Crates, each containing a Blue Power Core. Also, there are 3 Iron Crates, each containing a Red Power Core. Finally, there are 3 balloons in the sky, each containing a Yellow Power Core. Metal Madness attack patterns remain the same as it was in Team Chaotix's section. After draining the creature's health one last time, the boss will be defeated.
Following the boss battle, Metal Madness will complete his transformation, becoming Metal Overlord.