Magical King of the Swamp

If this card is in your hand: You can reveal 1 Fusion Monster in your Extra Deck and banish 1 material whose name is mentioned on it from your Deck, then Special Summon this card, and its name can be treated as the banished monster's if used as Fusion Material this turn. You can only use this effect of "Magical King of the Swamp" once per turn.