Eis Shenron shoots the energy blast by turning his hand into a modern blasting cannon, with the Dragon Ball inside his arm emitting the ki. In the Japanese version, he says "Fire" as he shoots the blast, but in the English dub, he merely shouts "Hold this for me".
Video Game Appearances
In Dragon Ball Xenoverse, it appears under the name Ice Cannon and is Eis Shenron's Ultimate Skill. It can also be obtained by the Future Warrior as a reward in DLC Parallel Quest Event: "The Shadow Dragons" which is part of the GT Pack 2 DLC. In the game, the user performs a quick spin before charging an icy cold ki blast to freeze whoever it hits. When performed by the Future Warrior, it is fired from the Warrior's left palm due to the lack of Eis Shenron's arm cannon.
In Dragon Ball Xenoverse 2, Ice Cannon returns as one of Eis Shenron's Ultimate Skills which can be obtained by the Future Warrior by summoning Shenron and wishing for more Ultimate Attacks (it can only be obtained after using this wish to unlock Time-Skip/Molotov) which will unlock both Ice Cannon and Nuova Shenron's Burning Spin. The Future Warrior in Xenoverse 2 performs it in the same manner as the Future Warrior from Xenoverse.