Juiblex

Juiblex is the Faceless Lord, a Tanar'ri patron of slimes, oozes, aboleths, and similarly slimy things. It manifests as a towering pile of putrescent ooze from which hundreds of red eyes peer.

Juiblex dwells in Shedaklah, the same layer of the Abyss as Zuggtmoy, the tanar'ri patron of fungi. They have warred for eons, though Juiblex has recently taken control of a greater portion of the layer during Zuggtmoy's imprisonment in the Temple of Elemental Evil on Oerth.

Shedaklah is cataloged as the 222nd layer of the Abyss by the Fraternity of Order.

Additional Resources:
Juiblex in the Fiendish Codex