A creature created in the Chimera Labs during Chapter 7, like its name implies, it cannot be killed and can defeat the player instantly by merely being touched. Instead, it needs to be avoided and run away from. It has a button on its back which switches it off, but the bird on its head will simply press the button again to revive it. It appears again in the toilets during Chapter 8 but it is still undefeatable.
The Ultimate Chimera appears on the New Pork City stage in Super Smash Bros. Brawl, and true to the series, getting bitten by the creature will result in an instant K.O. Though the button is visible on his back, it is impossible to press it and shut the chimera off. It is possible to send the chimera off the stage by destroying a breakable section of the floor when the beast is walking on top of it.