MAKUTA TERIDAX IS STILL ALIVE!

Lets analyze his supposed defeat: Mata nui smashed his head into a planet....so what? Teridax's body has been destroyed many times before, so why should this be any different? Example: At the end of "The Mask of Light" his and Takanuva's fused body was smashed under a giant door, and only the mask of light made it out, from which they were able to bring Takanuva back to life, but frankly Teridax didn't die either.

The thing about Teridax is that he's no longer so much a living being, he's more like a ghost or essence occupying a mechanical body, so if his body is destroyed his spirit just leaves and finds a new vessel. Another thing to keep in mind is that Teridax is nothing less than an absolute genius! He doesn't just make a plan, but a web of backup plans for every possible situation, including the possibility that he's defeated, so I can conclude that he was prepared, and of course escaped, Now hiding in Shadow form until he can acquire a new body!