Advanced 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).
Current rulings for this card are maintained by Konami.
Rulings data courtesy of Format Library — formatlibrary.com. Spotted an inaccuracy? Flag it in the Advanced forum — sourced change requests get reviewed.