Tribal Unity (SBC2-ENS08) - Speed Duel: Battle City Finals 1st Edition

"Harpie" monsters are also treated as "Amazoness" monsters and vice-versa, while they are on the field or GY. Once per Duel, you can discard 1 monster to make 1 "Harpie" or "Amazoness" monster you control gain ATK equal to the Level of the discarded monster x 200.