집중마법
마법물체나 부여마법을 목표로 정한다. 그 목표를 파괴한다.
조사한다. ("

, 이 마법물체를 희생한다: 카드 한 장을 뽑는다."를 가진 무색 단서 마법물체 토큰 한 개를 전장에 놓는다.)
If an effect refers to a Clue, it means any Clue artifact, not just a Clue artifact token. For example, you can sacrifice Wrench to pay for Alquist Proft, Master Sleuth's activated ability.
Clue is an artifact type. Even though it appears on some cards with other permanent types, it's never a creature type, a land type, or anything but an artifact type.
You can't cast a spell without choosing legal targets. If all of those targets become illegal, the spell doesn't resolve and you won't investigate.
You can't sacrifice a Clue to pay multiple costs. For example, you can't sacrifice a Clue token to activate its own ability and also to activate Alquist Proft, Master Sleuth's ability.