You can send 1 "Umi" from your hand, Deck, or face-up field to the GY; Special Summon 1 WATER monster from your hand. When your opponent activates a monster effect, or Spell Card or effect, while "Umi" is on the field (Quick Effect): You can negate that effect, then, you can make this card gain 600 ATK/DEF. You can only use each effect of "Electric Jellyfish" once per turn.