Bawabawa

Bawabawa

バワバワ
Bawabawa is a giant, eel-like hollow whose mask consists of a simple plate on his head with a pair of horns. He acts as both a pet and transportation for Pesche, Dondochakka, and Nel Tu. Bawabawa tends to throw fits for not being included in the group's super sentai-styled introduction sequences.

Initially, Pesche and Dondo say that Bawabawa can't survive without sand, thus explaining why Bawabawa doesn't follow the group into Las Noches. During a battle with Szayel Aporro Granz, however, Dondo reveals the ability to spit Bawabawa from his mouth. Pesche explains that Bawabawa is actually one of many spiritual combat insects that dwell within Dondo
(source: http://en.wikipedia.org/wiki/List_of_Bleach_hollows)