Sanguine Guard

The combination here is the whole pitch: first strike plus a regeneration ability priced low enough to use every combat. That pairing is the deliberate engine. First strike means it kills before it takes a hit, and the regeneration shield (cheap enough to leave mana up for it repeatedly) means the rare time something connects back, the creature survives to do it again. Most regenerators of its era asked you to choose between blocking and dying or holding back; this one blocks an attacker, deals its damage first, and walks away even if both creatures would otherwise trade. The math turns it into a near-impassable ground wall against single attackers and a recurring threat against a board that cannot all swing at once. The Phyrexian Zombie Knight typing is flavor scaffolding for the rate rather than load-bearing tribal text. What keeps the design honest is the mana tax: every regeneration costs you, so a player with enough simultaneous attackers or a way to remove it outside combat (exile, sacrifice effects, minus-toughness) can still get through. It is a card built around the interaction between damage timing and the regeneration window, asking the opponent to break a loop rather than win a single exchange.