Advanced format ruling
A Legendary Ocean
Card effect (current official text)(This card's name is always treated as "Umi".)
All WATER monsters on the field gain 200 ATK/DEF. Reduce the Level of all WATER monsters in both players' hands and on the field by 1.
Current rulings for this card are maintained by Konami.
Rulings data courtesy of Format Library — formatlibrary.com. Spotted an inaccuracy? Flag it in the Advanced forum — sourced change requests get reviewed.