Reality Smasher

Every attempt to answer it costs the answerer a card, and that tax is the whole point. A 5/5 with haste and trample is already a real clock, but the rider rewrites the usual math of dealing with a hasty threat: target it with a spell and the spell is countered unless its controller discards a card. You do not get to spend a clean removal spell for free. If they pay the tax, their removal resolves and the creature dies, but they have spent both a card and a discard to do it, an exchange that runs two-for-one against them. If they refuse, the spell fizzles and they have burned a card for nothing while the battering ram keeps swinging. Either way the aggressor comes out ahead on cards, which is a strange thing to say about a creature whose defense is that you are allowed to kill it. Against decks leaning on cheap spot removal, each answer becomes a lopsided exchange; against decks that cannot afford the extra card, the haste and trample close the game before the question matters. The demand for anchors the body to mana bases built to produce that specific colorless pip rather than something splashed into any pile of lands. It belongs to the line of colorless Eldrazi that ask you to break the symmetry of the stack rather than win combat outright, and it carries the crudest version of that idea: a threat that protects itself not with evasion or resilience but by making interaction hurt.