Seiyaryu + Bolt Escargot → Twin-headed Thunder Dragon

Seiyaryu + Bolt Penguin → Twin-headed Thunder Dragon

Seiyaryu + The Immortal of Thunder → Twin-headed Thunder Dragon

Seiyaryu + Electric Snake → Twin-headed Thunder Dragon

Seiyaryu + Mega Thunderball → Twin-headed Thunder Dragon

Seiyaryu + Electric Lizard → Twin-headed Thunder Dragon

Sanga of the Thunder + Parrot Dragon → Twin-headed Thunder Dragon

Sanga of the Thunder + Harpie's Pet Dragon → Twin-headed Thunder Dragon

Sanga of the Thunder + Metal Dragon → Twin-headed Thunder Dragon

Sanga of the Thunder + Sky Dragon → Twin-headed Thunder Dragon

Sanga of the Thunder + Thunder Dragon → Twin-headed Thunder Dragon

Sanga of the Thunder + Stone D. → Twin-headed Thunder Dragon