From Dragon Ball Encyclopedia, the ''Dragon Ball'' wiki
Tullece forms a fiery ring of energy with electricity sparking around it between his palms and throws it at his opponent. The resulting explosion is quite powerful, and apparently enough to kill a Great Ape. The downside of this technique is that the center of the ring is empty. This means that if the targets are small enough, they will slip past the hollow center and be unharmed by the attack, as seen in Son Gohan's case when he was restored to his base form by Son Goku.