Runuganga

(sometimes incorrectly romanized as Lunuganga), is a giant Hollow made of sand whose head resembles a sand castle.

Character Outline
He is the Guardian of the White Sands, and acts under orders to protect Las Noches from intruders. Being made of sand, he's immune to most physical and Kidō attacks, simply regenerating from almost any wound without fail. He can control the sand around him to attack, creating sinkholes and tornadoes. Though this makes him practically unstoppable in Hueco Mundo's desert terrain, it also makes him extremely weak against water and ice attacks, and he is easily dispatched by Rukia Kuchiki using her Shikai. In the anime, Runuganga is said to have many bodies since he basically just sand; killing his easily-dispatched, individual bodies does not kill him as a whole, so only an almost impossibly broad and powerful attack could ever hope to truly kill him.

Hueco Mundo arc
Runuganga blocks the passage of Yasutora Sado, Ichigo Kurosaki, Uryū Ishida, Nelliel Tu Odelschwanck, Dondochakka Bilstin, and Pesche Guatiche during their journey to Las Noches. The three friends from the Human World attack the Guardian relentlessly, but their attacks all fail, as they are similar and nature and, Runuganga can simply reform after being attacked by them. They are eventually saved by the arrival of Renji Abarai and Rukia Kuchiki. Rukia uses her Shikai's second dance, Hakuren, and defeats Runuganga. However, as a last act of spite, he opens a sinkhole that sends the group tumbling into the Forest of Menos.

Powers and Abilities
Sand Manipulation: Runuganga, as guardian of the Hueco Mundo desert, has the innate ability to manipulate the sand. He is seen using this ability to create massive pits in order to trap the group of Shinigami and Arrancar trying to infiltrate Las Noches.

Regeneration: As seen in his battle with Ichigo, Chad, and Uryū, Runuganga has the ability to regenerate lost body parts and wounds.

Unhinged Jaw: Runuganga also has the ability to widen his jaw to such a size as to swallow the entire group of his opponents in one fell swoop.