Nashi, Moon's Legacy is a rare Legendary Creature — Rat Shaman card from March of the Machine: The Aftermath (MAT), collector number 89. Current market price: $0.55 (foil $0.49), TCGplayer market prices via Scryfall.
Menace, ward {1} Whenever Nashi attacks, exile up to one target legendary or Rat card from your graveyard and copy it. You may cast the copy. (You still pay its costs. A copy of a permanent spell becomes a token.)