Battikaroa

Battikaroa is a giant Hollow made of sand, similar to Runuganga. Battikaroa has a large, bluish-grey body that is made from sand, similar to Runuganga. He has a series of upward-curving spikes around the base of his neck as well as a number of protrusions around his head. His arms are long, with the forearms being much thicker than his upper arms. His Hollow hole is in the center of his chest. Battikaroa has markings on his abdomen and wears a low-slung cloth around his waist. He also wears plain bracelets on both wrists and on his upper arms. He battles against Renji Abarai and Yasutora Sado while they are fighting hordes of Hollows below the fifth tower in Las Noches.

At the beginning of the battle, Renji tries to attack the midsection of Battikaroa. This does not work as his sword is almost swallowed by the Hollow. Sado saves Renji's sword by helping to pull it out. Eventually, Sado tries to use La Muerte on the Hollow, which is able to cause a crack up that runs up to a location right below the mask, but the Hollow hits Sado off before it cracks the mask. Eventually, they figure out that Battikaroa has one weakness; his head. After numerous failed attempts at breaking the mask, Sado attacks with his La Muerte technique, which hits Battikaroa's bottom.

While he's preoccupied with Sado, Renji fires a Hikotsu Taihō blast at the Hollow's mask, defeating him. (Source: Bleach Wiki)