Survive the Night
Instant
Target creature gets +1/+0 and gains indestructible until end of turn. (Damage and effects that say "destroy" don't destroy it.)
Investigate. (Create a Clue token. It's an artifact with ", Sacrifice this token: Draw a card.")
The longest nights are measured not in hours, but in heartbeats.
Svetlin Velinov
The List (PLST)
• #SOI-41Rulings
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.
(wotc • 2016-04-08)
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.
(wotc • 2016-04-08)
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.
(wotc • 2016-04-08)
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.
(wotc • 2016-04-08)
Rulings
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.
(wotc • 2016-04-08)
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.
(wotc • 2016-04-08)
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.
(wotc • 2016-04-08)
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.
(wotc • 2016-04-08)