Colossus, Steel Stalwart

The indestructibility here is deliberately half-a-turn: it switches on during your turn and switches off during everyone else's, which is a precise inversion of the usual protection package. Most indestructible bodies are hardest to kill when it isn't your turn, when opponents are trying to break through defenses at instant speed; this one is bulletproof while swinging and vulnerable while sitting back. That reads as a fixed-point 4/5 rather than a true anchor, and the split does the balancing work: you can attack into removal-heavy boards without fear, but you cannot leave him parked as an untouchable blocker across the table's turns. Beyond the self-protection, the flat +1/+1 to your other Mutants reframes him from a solo threat into the payoff at the top of a tribal curve. That combination (a self-protecting attacker who also scales a board of small creatures) is a familiar white-weenie or elf-lord shape rendered in green, with the indestructible clause standing in for the trample or evasion a lord usually wants. His anthem doesn't apply to himself, so the buff is entirely about the team he leads rather than the size he reaches. He is built to be the front of a wide, aggressive Mutant board, and the timing on his indestructibility tells you exactly how that board is meant to attack: all in, on your turn, and then brace for the swing back.