If you control a monster whose original name is "Obelisk the Tormentor": Negate the effects of 1 Effect Monster your opponent controls, and if you do, destroy it, and if you do that, for the rest of this turn, the effects of that monster are negated, as well as the activated effects and effects on the field of monsters with the same original name, then, if you activated this card during your Main Phase, you can apply this effect.