Cheapest priced copy (Murders at Karlov Manor Commander): $0.49 at Card Kingdom, near mint, their price list as of .
Armed with Proof 
Enchantment · Rare · Murders at Karlov Manor Commander · #9
When this enchantment enters, investigate twice. (To investigate, create a Clue token. It's an artifact with "{2}, Sacrifice this token: Draw a card.")
Clues you control are Equipment in addition to their other types and have "Equipped creature gets +2/+0" and equip {2}.
Legal inCommanderLegacyVintage
Not legal inBrawlStandardPioneerModernPauper
2 printings · $0.49 to $0.79 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Murders at Karlov Manor Commander | 9 | Rare | $0.49 | — |
| Murders at Karlov Manor Commander | 320 | Rare | $0.79 | — |
8 rulings from Wizards of the Coast
- 2 February 2024Some abilities trigger "whenever you sacrifice a Clue". Those abilities trigger whenever you sacrifice a Clue for any reason, not just to activate a Clue's activated ability.
- 2 February 2024Clue 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.
- 2 February 2024An Equipment without reconfigure that's also a creature can't be attached to anything. You can activate its equip ability, but it won't become attached. For example, if you control both Red Herring and Armed with Proof, Red Herring will be an Artifact Creature – Clue Equipment Fish with "Equipped creature gets +2/+0" and equip {2}, but activating its equip ability won't result in it becoming attached to the target creature.
- 2 February 2024If you control more than one Armed with Proof, creatures equipped with Clue Equipment will get +2/+0 for each Armed with Proof you control. The equip cost is still {2}.
- 2 February 2024Some spells and abilities that investigate may require targets. If each target chosen is an illegal target as that spell or ability tries to resolve, it won't resolve. You won't create any Clue tokens.
- 2 February 2024If 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.
- 2 February 2024Clues stop being Equipment if Armed with Proof leaves the battlefield. If any of them are attached to creatures at that time, they become unattached.
- 2 February 2024You 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.