Cero

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

Description
is a form of attack used by menos, arrancar and vizards. 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.

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 those 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 Sincrético
. 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.

Gran Rey Cero
is an Espada exclusive Cero. It is performed by mixing and Arrancars own blown with in the cero and is power is much greater compared to a regular cero and different color. This attack was first used by Grimmjow Jeagerjaques in order to incite Ichigo Kurosaki in to dawning his mask.

Others
While most cero are red. Ichigo's Hollow form's cero is tri-focused and pink, while Ulquiorra Schiffer's is green.