Number 100: Numeron Dragon (Ultra Rare (Blue))

2 Level 6 monsters
Once per turn, during either player's turn: You can detach 1 Xyz Material from this card, then target 1 face-up monster on the field that was Special Summoned from the Extra Deck; change it to face-down Defense Position. If this face-up card in its owner's control is sent to your Graveyard or banished by your opponent's card effect: You can Special Summon this card in face-down Defense Position. If this card is flipped face-up: Send 1 card on the field to the Graveyard.