Card Rulings:Trishula, the Dragon of Icy Imprisonment

OCG Rulings

 * When you Fusion Summon "Trishula, the Ice Prison Dragon", its materials must be monsters on your field or in your hand. Therefore, when Special Summoning "Trishula, the Ice Prison Dragon" with the effect of "Dragon’s Mirror", you must be able to use only monsters in your Monster Zone as the materials. (If the set of Fusion Materials that does not include monsters in your Graveyard is unavailable, you cannot activate "Dragon’s Mirror" to Special Summon "Trishula, the Ice Prison Dragon".)