
Whenever you cast an instant or sorcery spell, investigate. (Create a Clue token. It's an artifact with ", Sacrifice this token: Draw a card.")
"Every answer seems to lead to a more terrifying question." —Jace Beleren
Illustrated by Daniel Ljunggren
Released on April 8, 2016
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 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.
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.