Edison format ruling
Horn of Heaven
Card effect (current official text)When a monster(s) would be Summoned: Tribute 1 monster; negate the Summon, and if you do, destroy that monster(s).
Rulings
- Horn of Heaven cannot be used to negate a Special Summon that results from a Spell, Trap, or effect of an Effect Monster Card. You cannot use Horn of Heaven to negate a Special Summon from Monster Reborn, Polymerization, Premature Burial, Call of the Haunted, Elegant Egotist, Fusion Gate, a RItual Spell Card, Giant Rat, Mystic Tomato, Marauding Captain, Spear Cretin, Cyber Jar, Van'Dalgyon the Dark Dragon Lord, Tualatin, etc.
- Horn of Heaven can be used to negate the Special Summon of a monster with an inherent Special Summon effect that does not start a Chain, like Dark Armed Dragon, Dark Necrofear, Cyber Dragon, Gladiator Beast Heraklinos, Elemental Hero Magma Neos, etc.
Rulings data courtesy of Format Library — formatlibrary.com. Spotted an inaccuracy? Flag it in the Edison forum — sourced change requests get reviewed.