From Dragon Ball Encyclopedia, the ''Dragon Ball'' wiki
The Dimension Scream (異次元 空間, Ijigen Kūkan; Literally meaning "Different Dimension Space") is a supportive technique used by Super Boo and Gotenks. The user lets out all of their energy in a high pitched scream, ripping through the dimensions.
Dragon Ball Z
Super Boo and Gotenks both used this technique in order to escape from within the Hyperbolic Time Chamber.
Super Boo (Goten, Trunks, Piccolo, and Gohan absorbed) later tried to use the Dimension Scream as a last resort against Super Vegetto. Super Boo (Goten, Trunks, Piccolo, and Gohan absorbed) claimed that the technique possessed enough power to destroy the whole universe, and thus created an energy shield to protect himself from his own attack. Vegetto broke through the energy shield, however, and punched Super Boo in the face before he could finish the attack.