Sample Collector is a uncommon Creature — Troll Detective card from Murders at Karlov Manor (MKM), collector number 175. Current market price: $0.05 (foil $0.07), TCGplayer market prices via Scryfall.
Whenever this creature attacks, you may collect evidence 3. When you do, put a +1/+1 counter on target creature you control. (To collect evidence 3, exile cards with total mana value 3 or greater from your graveyard.)