A Fusion Spell Card is a type of card used in the Yu-Gi-Oh! trading card game that allows players to combine two or more monsters to create a more powerful creature known as a Fusion Monster. This process typically requires specific monster cards and a Fusion Spell Card to perform the fusion. To use a Fusion Spell Card, players must have the required materials on the field or in their hand. Once activated, the card enables the player to summon the Fusion Monster from their Extra Deck, enhancing their strategy and gameplay options.