Slime Molding

The whole spell collapses to one variable: every point of mana past the green pip becomes a point of power and a point of toughness. That clean conversion is the design's entire appeal and its entire limit. Pay six, get a 5/5; pay eleven, get a 10/10. There is no rider attached, no trample, no haste, no second body, just a vanilla Ooze whose size is whatever you could afford that turn. Green has a long line of these mana-into-stats sorceries and instants, and most of them justify the slot with something extra: a creature that fights as it lands, a token that gains a keyword, a flash window to ambush a blocker. This one strips all of that away and asks the X/X to stand on the strength of its size alone, which is a high bar for a board that usually wants reach or evasion or resilience instead of raw numbers. The sorcery timing matters more than the rate does: you cannot hold the mana up to respond, you cannot bluff it, you commit on your own turn into open mana, and a single removal spell erases the entire investment for one card. It is the most honest version of a green idea that other cards have learned to dress up, and the dressing is usually the point.