Tunneler Wurm

Eight mana for a 6/6 whose only printed ability is a regeneration shield bought with discarded cards: this is the kind of bulk green fatty that early-era sets turned out by the handful, a finisher with a small insurance policy stapled to a big body. The regeneration is where the design gets quietly self-defeating, because it cuts against the very situations it claims to protect. Discarding to keep the body alive matters most in a grindy attrition fight, but by the time you have paid this much, your hand is rarely deep enough to feed the ability more than once or twice, and the cards you pitch are cards you would rather have drawn into. Regeneration also fails against the answers that actually trouble a creature this expensive: exile, bounce, sacrifice effects, and anything that drops toughness below the lethal line. So the shield catches the threats it does cover (combat death, direct damage, and destroy effects) while leaving the body exposed to the answers most likely to be aimed at it. It is honest design for its rarity and era, but the math on the policy never quite favored the holder; the regeneration covers the deaths that were never the problem and folds to the ones that were.