Vikavolt-GX has been revealed from Sun & Moon Strengthening Expansion Pack, which will be released in Japan on January 27th. Thanks goes to Bangiras for the translation!
[L] Charge Beam: 50 damage. Attach 1 Energy card from your discard pile to this Pokemon.
[L][C][C][C] Super Zap Cannon: 180 damage. Discard 2 Energy attached to this Pokemon.
[L][C][C][C] Gigatron GX: Does 60 damage to each of your opponent’s Benched Pokemon. (Don’t apply Weakness and Resistance for Benched Pokemon.) (You can’t use more than 1 GX attack in a game.)
When your Pokemon-GX is Knocked Out, your opponent takes 2 Prize cards.
Weakness: Fighting (x2)
Resistance: Metal (-20)