Lazav, Familiar Stranger

Every earlier Lazav was a graveyard mimic that paid for its copying with mill: you fed the yard, then wore whatever creature died into it. This incarnation reroutes the whole engine through crime. The trigger no longer keys off self-mill; it keys off aggression, off targeting an opponent or something they control, and it pays out twice for the same act: a lasting +1/+1 counter that grows the 1/4 body toward a real clock, plus the option to exile a card from any graveyard and, if it's a creature, become a copy of it until end of turn. The once-per-turn clause is the discipline. A crime-heavy deck commits crimes constantly, but the ability fires automatically on the first crime each turn and then sits dormant, so every additional crime that turn is pure interaction with no bonus attached; the counter and the copy come off whatever you happened to point first. The copy being optional and temporary matters as much as the copy itself: exile a threat from an opponent's graveyard, wear it for a swing, then shed it back to a hardy 1/4. The exile clause does quiet graveyard hate on the side, stripping recursion targets while it builds. What makes this version singular is the fuel: interaction is the input. Every removal spell and targeted effect that qualifies as a crime doubles as a trigger, so a long-running shapeshifter identity gets rebuilt on the premise that being a nuisance to the opponent is exactly what feeds it.