The Morbuzakh was created by Teridax years before he impersonated Turaga Dume. The plant's purpose was to drive the Matoran into the Coliseum of Metru Nui, where they would be forced into pods, have their minds erased, and enslaved.
The Morbuzakh's King Root was planted by Makuta in Ta-Metru, the Great Furnace to be exact. The lava of the Furnace caused it to slowly grow, until it finally spread across the city, causing trouble all over Metru Nui.
After a long period of Morbuzakh attacks, the six Toa Metru finally arrived, their first mission being to secure the six Great Disks, one in each Metru, to defeat the plant. Though it tried to stop them, the Toa, with the aid of six Matoran, succeeded in claiming the disks.
The six Toa and Matoran then went to encounter the Morbuzakh's king root. However, the group was attacked by Morbuzakh seeds, and the six Matoran formed a Matoran Nui, to help them.
The Toa Metru got through to the King Root, and it tried one last time to defeat the Toa and claim the Great Disks. However, the Toa succeeded in activating the Great Disks, the combined power of the disks causing the death of the Morbuzakh.
The Morbuzakh's prototype was the Karzahni, a sentient creature. This fact caused it to rebel against Makuta Teridax, causing the necessity of a less intelligent creature. It wanted to become stronger than him and eat him. Bits of this plant are used for flotation in airships.