Pool of Vigorous Growth

The lever you pull is mana value, and the machine hands back a random creature drawn from the entire game's card pool, not from anything in your deck. That inheritance runs straight back to Momir Vig, Simic Visionary as a Vanguard avatar and every Momir Basic table since: name a number, pay it, and take whatever creature the client rolls at that value. Building the effect into an artifact you tap and fuel with a discarded card changes the register from a full-format novelty mode to a repeatable in-game engine, and randomness is what pays for it. Because you cannot aim the effect, the payoff lives in your choice of X: the density and quality of creatures at a given mana value across all of Magic is the odds table you are betting into, and higher numbers cost more to reach but tend to land bigger bodies. The sorcery-speed clause slams the door on instant-speed shenanigans, keeping this an engine you develop across turns rather than a combat-step ambush, while the discard cost quietly converts dead cards in hand into fuel. Generating a token copied from a card outside the game is an effect the digital client can resolve on the fly and paper cannot cleanly reproduce without a physical token library on hand. What you build around is not your own creatures but the game's, and the whole card is a wager on what a random pull at your chosen number is worth.