Phyrexian Juggernaut

Take the original Juggernaut, a 5/3 whose only rules text was that it had to attack every combat, and reskin it with Phyrexian biology. The forced-attack clause that made the first one a reckless brawler does something stranger once infect changes the damage type: every swing becomes a forced injection of poison, and the creature cannot stay home as a blocker even when discretion would serve you better. Ten poison counters end a game, so a body this size connecting twice puts a player on a clock that conventional life totals cannot describe. The compulsion to attack is the cost the design charges for the raw output: an infect creature you cannot keep back is an infect creature your opponent can plan around, baiting it into a removal spell or a profitable block by knowing exactly when it has to commit. A poison threat that telegraphs its own aggression behaves nothing like the infect creatures that came with an off switch; the rider does the balancing work the keyword would otherwise hand you for free. At six mana for a 5/5 it sits at the heavy end of the keyword's curve, a finisher rather than an early pressure piece, and the forced-attack clause is the reason it never displaced the cheaper, more controllable poison threats that defined the archetype around it.