Predator Ooze

The triple-green pip is the whole tension here: a 1/1 that costs three colored mana looks indefensible on rate, until you notice it cannot be removed by the most common answers in the game. Burn bounces off it; wraths leave it standing. The only clean exits are exile, bounce, sacrifice effects, and edicts. Everything that tries to trade with it just feeds it. Each attack adds a counter, and every creature it kills in combat adds another, so the body that started embarrassingly small snowballs past blockers within a couple of turns. The design problem it solves is how to build a growth engine that opponents cannot interrupt with the cards they were already holding: indestructible removes the usual relief valves, and the two counter-triggers turn the act of contesting it into the thing that makes it bigger. The cost of that resilience is the body it ships with and the speed it grows at. On the turn it lands it is a 1/1 that contributes nothing, and indestructible does nothing against a large enough blocker that simply holds the line: the Ooze survives, but so does the wall in front of it, and the game stalls until it gets big enough to outclass the board. It is a creature built to punish a metagame that leans on destroy effects, and to fold quietly to one that leans on bounce, exile, and edicts instead.