Negación

is the term used for the fields used by Hollows to rescue fellow Hollows. Only the Gillian-class Menos have shown the ability to use Negación.

Description
Negación are fields surround a target in a square beam of light that isolates the target from the dimension they are currently in, making it impossible to harm them. The field then pulls the target towards the Menos that created the field.

All Gillian-class Menos can use Negación, but only if the target is outside of Hueco Mundo (such as Living World, Soul Society, etc.) They only use the technique to aid their comrades or fellow Hollow, which during Aizen's escape, were Kaname Tōsen, Gin Ichimaru and Sōsuke Aizen. General Yamamoto stated that once that beam of light surrounded them, it was over, because there was no way to reach them as the Negación field is impenetrable.