Crystal Beast Emerald Tortoise (SGX1-ENF05) [Speed Duel GX: Duel Academy Box]

Once per turn: You can target 1 monster you control that attacked this turn; change that target to Defense Position. If this face-up card is destroyed in a Monster Zone, you can place it face-up in your Spell & Trap Zone as a Continuous Spell, instead of sending it to the GY.