Card Rulings:Blue-Eyes Doom Dragon

"Blue-Eyes Ultimate Dragon" + "Blue-Eyes White Dragon" + "Blue-Eyes White Dragon"

A Fusion Summon of this card can only be done with the above Fusion Material Monsters. <This card only only be Fusion Summoned by using "Blue-Eyes Ultimante Dragon", "Blue-Eyes White Dragon" and "Blue-Eyes White Dragon" with "Polymerization" or "Dragon's Mirror" Etc.

This card cannot be destroyed by card effects. < this is Continuous Effect Which no card can negate.

Once per turn: You can discard 1 card; destroy all monsters OR all Spell/Trap Cards your opponent controls. < You can only Activate this Effect once per turn, By discarding a card "Monster", "Spell" or "Trap" card. this effect only destroy's the Discarded card type. "Example: Discarded "Gearfried the Iron Knight" for the Discard cost, Then all Monsters your opponent(s) controls are Destroyed. This is applyed to Spell's and Trap cards. And neating this effect wont destroy it. Thus the power within this monster is so great it's only Foes are the Egyptian Gods. "Obelisk the Tormentor", "Slifer the Sky Dragon" and "The Winged Dragon of Ra"