Subterror Guru

FLIP: You can add 1 "Subterror" card from your Deck to your hand, except "Subterror Guru". You can target 1 other face-up monster on the field; change that monster, also this card, to face-down Defense Position. This is a Quick Effect if you control another "Subterror" card. You can only use each effect of "Subterror Guru" once per turn.