Forum:Negate Special Summon

I need help on the ruling of black horn of heaven. It says you can negate a special summon of a monster. Does it negate a gladiator beast sp summon from the deck? Or negating a special summon of a Grandmaster of the six samurai. Thanks. I am confused due to the ruling. Tanhopkins93 08:19, 8 December 2008 (UTC)