DarkFiend/Effect. At the end of a Damage Step: You can Special Summon this card from your hand. You can send 1 Trap from your hand or from among face-down cards you control to the GY; destroy all other monsters in this card's column. If this card in the Monster Zone is destroyed by battle or card effect and sent to the GY: You can target 1 card in your GY; roll a six-sided die, and if the result is 6, add that card to your hand. You can only use each effect of "Thunder Ball" once per turn.