Gatoledo (name may vary by source)
A towering guardian composed entirely of sand with a head shaped like a sand castle. He serves as protector of the White Sands and follows orders to keep intruders away from Las Noches.
His sand body gives him a significant advantage—he can regenerate from nearly any physical or magical attack, making him nearly invulnerable across most of Hueco Mundo's desert landscape. He's skilled at manipulating the sand around him to create sinkholes and tornadoes. The catch? He's completely defenseless against water and ice attacks. Rukia Kuchiki took him down without much trouble using her Shikai, demonstrating just how badly his weakness exploits can turn the tables.
In the anime, it's suggested that GaToledo exists as multiple bodies scattered throughout the sand. Destroying individual segments doesn't actually kill him—they just reform. Only a catastrophically powerful, all-encompassing attack could potentially defeat him for good, which is why he's so difficult to truly put down despite being vulnerable to the right opponent.
Content compiled by AnimeList.moe from publicly available sources.