Ghostrick Mummy

Cannot be Normal Summoned, unless you control a "Ghostrick" monster. Once per turn: You can change this card to face-down Defense Position. While this card is face-up on the field, you can Normal Summon 1 "Ghostrick" monster in addition to your Normal Summon/Set. (You can only gain this effect once per turn.) You cannot Special Summon any monsters, except DARK monsters.