Armed with Proof is a rare Enchantment card from Murders at Karlov Manor Commander (MKC), collector number 9. Current market price: $0.33, TCGplayer market prices via Scryfall.
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}.