Memory Vampire

The join between milling and casting is what makes this a puzzle rather than a beater. Combat damage fills a defending player's graveyard, and then collect evidence 9 asks you to exile nine mana value worth of cards from your own yard to steal one nonland card back out of the pile you just built. That is a genuine two-step engine: the flying body seeds the target graveyard on one turn, and the evidence payment converts your own graveyard into a free cast. The 4/4 flier is small for six mana, so the card is priced on the theft, not the beatdown. The elegant part is the self-fueling loop between the mill trigger and the evidence cost: milling a player deep enough to reach their good spells simultaneously requires you to have banked enough in your own graveyard to pay the nine, which the card's own combat damage helps supply over successive attacks. The free cast targets whatever the defending player has lost to their graveyard, so a deeper grind puts a better card in reach, and the mill can hit multiple players at once even though the steal is limited to the one you attacked. A design built around a detective's methodical work: collect the evidence, then take exactly one thing from the person you were investigating.