Ancient Silver Dragon

This is the d20 mechanic scaled up to its most absurd conclusion: a creature that turns a single connected attack into a card-draw payout ranging from one card to twenty, with the dispersion baked in as the whole point. Most card-draw effects fix their yield precisely because variance makes them hard to cost; here the design leans the opposite way, pricing a flying 8/8 body high enough that the roll becomes gravy rather than a plan, then handing you a bomb that can whiff into a single card or refill your grip past any reasonable count. The rider that removes your maximum hand size for the rest of the game is the quiet tell that the designers expected the high end to land: a natural twenty means nothing if the discard step claws back most of what you drew, so the ability protects its own ceiling. Structurally it belongs to the small family of Dungeons & Dragons crossover creatures that fold the tabletop d20 into a Magic trigger, and among them it sits at the swingiest extreme, since damage-to-a-player is the easiest condition for a large evasive threat to satisfy and the payout reaches as high as the die allows. The result is a finisher that already wins the race on its stats and treats the dice as a reason to keep swinging rather than close the game.