Lemuria, the Forgotten City (Legendary Duelists: Duels From the Deep LED9-EN055) - Common Yu-Gi-Oh! Card

This card's name is treated as "Umi". All WATER monsters gain 200 ATK and DEF. Once per turn, during your Main Phase: You can have all WATER monsters you currently control gain Levels equal to the number of WATER monsters you currently control, until the End Phase.