Hunting Horn - Doom of Dimensions (DOOD)

Fusion Summon 1 EARTH Warrior Fusion Monster from your Extra Deck, using Warrior monsters from your hand or field, then if you activated this card during the Battle Phase, you can choose monsters your opponent controls, up to the number of materials used from the hand for this Fusion Summon, and their ATK become halved until the end of the Battle Phase. You cannot declare attacks the turn you activate this card, except with EARTH Warrior monsters. You can only activate 1 "Hunting Horn" per turn.