Bioplasm

Combat math you cannot do at the start of the turn is the whole pitch here: declare an attack with this 4/4, flip the top of your library, and either nothing happens or a buried fatty doubles its size on the spot. The variance is the point. Build with high-power creatures up top and accept that the swing might whiff into a land or a sorcery. It is a randomized version of an effect that more reliable designs handle through reveal-and-choose or graveyard recursion: this one trades selection for surprise, and exiles the card win or lose, so the cost is permanent regardless of the outcome. That permanence is what keeps the body honest. This is not a recurring engine; it is the top of your library spent one card at a time for a chance at a blowout combat step. The result reads as a 4/4 but plays like a coin flip toward something much larger, and the deckbuilding tension it creates (curve the top of your library high enough to matter, but not so high you stall) is more interesting than the rate alone suggests. An attacker that rewards top-heavy decks and punishes thin ones, with the gamble baked into every declaration.