It’s a Shark eat Shark world.
RD/KP01-JP036 交戦魚サメガロン Kousengyo Samegalon (Warfish Sharkmegalon)
Level 7 WATER Fish Effect Monster
Requirement: You can activate this by sending 1 monster (WATER-Attribute) from your hand to the Graveyard.
Effect: Select 1 Defense Position monster your opponent controls and change it to face-up Attack Position.