Thrun, the Last Troll

The closest thing green ever got to an uncounterable, un-killable threat in one slot. Most resilient creatures pay for their durability with a fragile body or a steep price; this one stacks three independent layers of protection on a clean 4/4 for four. The uncounterable clause beats the answer on the stack. Hexproof beats the targeted answer on the battlefield: every point removal spell, every bounce, every tap-down your opponent might reach for needs a target this creature denies them. And regeneration, cheap enough to hold up multiple times a turn, beats the board wipe and the unfavorable block. What is left to kill it: a sacrifice or edict effect that makes you choose the creature yourself, a mass-destruction spell that exiles rather than destroys (or otherwise denies regeneration), or a chump-and-pray race. Narrowing the kill-window to those few outs is what the design is built around. Green has long been the color that asks "how do you actually deal with this?" and answers by stripping the usual outs one at a time, and few creatures strip as many at once as this troll does. The tradeoff is that all three abilities are purely defensive; nothing here generates advantage or closes faster than four power a turn. It is a body built to survive interaction rather than to dominate, which is exactly the green conceit it embodies: not the biggest thing on the board, just the thing you cannot make go away.