"Elemental HERO Neos" + "Neo-Spacian Dark Panther" Must first be Special Summoned (from your Extra Deck) by shuffling the above cards you control into the Deck. (You do not use "Polymerization".) If this card is not already targeting a monster with its effect: You can target 1 face-up Effect Monster on the field; while you control this face-up card, that target's effect on the field is negated. During the End Phase: Shuffle this card into the Extra Deck.
Marine Neos is worse. Your using an extra card in your Main Deck that could easily be a brick and a slot in your Extra Deck in a Deck that heavily uses the Extra Deck for what, 300 Extra ATK and DEF and the ability to activate its effect without discarding?