Cero

Cero is the strongest single shared attacked by upper-level Hollows

Description
is a form of attack used by high-power Hollows. It consists of firing a blast of concentrated energy at the target. While most are fired from the mouth, some are capable of firing from their hands, fingers and such.

While the power of the Cero is dependant on the strenght of the user (i.e. the stronger the user the stronger the attack), they are soe who have come with their own variation

Cero Doble
Cero Doble, Spanish for "Double Zero" is a variation performed by Neliel Tu Oderschvank, by swallowing her opponets cero and returning it back to the user along with her own cero. This attack was first seeing ussed against Nnoitra Jiruga.

While on her child for of Nel Tu is only able to returned the Cero fired by her opponnet as seen used against Dordonii Alessandro Del Socacchio.

Cero Cincretico
Cero Cincretico, Spanish for "synchronized Zero" is a variation performed by Dondochakka Bilstin and Pesche Guatiche by combinating their respecting cero's. This attack was first seen being ussed against Szayel Aporro Granz.

Beautiful Charlotte Cuulhorn's Final Holy Wonderful Pretty Super Magnum Sexy Sexy Glamourous Cero
This variation is performed by Charlotte Cuulhorn. Despite it's long name and the shape of heart it is just and ordinary Cero as noted by Yumichika Ayasegawa.

Others
While most Cero are red. Ichigo's hollow form's Super-Cero is tri-focused and pink. Ulquiorra Schiffer's is green.