Zagoth Mamba

Mutate paid its designers back most cleverly with support pieces like this: a body cheap enough to cast on turn one, and a trigger that fires not when this snake does anything, but when another creature mutates onto it. The Mamba itself has no mutate ability; it sits at the bottom or the top of a pile as a passenger, and every time you build the stack higher by mutating another non-Human creature onto it, the -2/-2 fires again. What would normally be tempo tax (spending mana to grow one creature out of several) becomes board control folded into the same line of play. A mutate deck rebuilding its pile after a wrath gets a free shrink each time it adds a body, clearing a small blocker or picking off a token as a rider on an act it wanted to do anyway. The single black pip and the 1/1 frame keep it honest as a floor: cast it early and it trades or chumps; commit it to a mutation and it turns into repeatable removal that scales with how deep you go. That is the quiet trick the mutate mechanic distills into one uncommon: a threat and a removal spell occupy the same slot, and the removal keeps refiring as long as the pile keeps growing.