Gem-Knight Aquamarine (HA05-EN020) - Hidden Arsenal 5: Steelswarm Invasion Unlimited

Gem-Knight Sapphire + 1 "Gem-Knight" monster // Must first be Fusion Summoned (from the Extra Deck) using the above Fusion Material Monsters. If this card attacks: Change it to Defense Position at the end of the Battle Phase. When this card is sent from the field to the Graveyard: Target 1 card your opponent controls; return it to the hand.