By summoning all his Electric Slime, Rage Shenron is able to encase himself in a massive version of his own body - taking on his Super form. The giant body's belly has a type of dome on the navel located exactly where its normal form has the Five-Star Dragon Ball, which is where Rage Shenron resides and controls all functions of the massive version of himself. This form protects Rage Shenron by absorbing the impact of attacks and rebounding them at the source. Rage Shenron can also release slime tendrils from his construct to trap opponents or to absorb electricity, increasing the mass of his slimy armor.
Rage Shenron uses this technique after Goku and Pan survived when he attacked them with his Electric Slime. During the battle, the Electric Slime Body Build displays the ability to deflect Goku's 10x Kamehameha and Pan's Masenkos. Rage Shenron also uses the form to attack his opponents and shoot the Dragon Thunder with more power.
In the Dragon Ball Heroes: Victory Mission manga, Rage Shenron uses this technique in order to grow to giant size to battle Super Saiyan 4 Broly, however, Broly easily defeats him using a Penetrate! like attack.