Sea King Dragon + Bolt Escargot → Twin-headed Thunder Dragon

Sea King Dragon + Bolt Penguin → Twin-headed Thunder Dragon

Sea King Dragon + The Immortal of Thunder → Twin-headed Thunder Dragon

Sea King Dragon + Electric Snake → Twin-headed Thunder Dragon

Sea King Dragon + Mega Thunderball → Twin-headed Thunder Dragon

Sea King Dragon + Electric Lizard → Twin-headed Thunder Dragon

Spike Seadra + Kaminari Attack → Twin-headed Thunder Dragon

Spike Seadra + Tripwire Beast → Twin-headed Thunder Dragon

Spike Seadra + Bolt Escargot → Twin-headed Thunder Dragon

Spike Seadra + Bolt Penguin → Twin-headed Thunder Dragon

Spike Seadra + The Immortal of Thunder → Twin-headed Thunder Dragon

Spike Seadra + Electric Snake → Twin-headed Thunder Dragon