Ghostrick Siren (BACH-EN014) [Battle of Chaos]

Cannot be Normal Summoned, unless you control a "Ghostrick" monster. Once per turn, during your Main Phase: You can change this card to face-down Defense Position. If this card is Normal Summoned or flipped face-up: Send the top 2 cards of your Deck to the GY, then if either card was a "Ghostrick" card, you can apply 1 of these effects.
<br>• Add 1 "Ghostrick" Spell/Trap from your Deck to your hand.
<br>• Change 1 Effect Monster your opponent controls to face-down Defense Position.