Ambuscade

The fight spell, rewritten so green stops losing the trade it picks. Classic fight effects (Prey Upon, Pit Fight, and their kin) deal damage in both directions: your creature hits theirs, theirs hits yours back, and an unfavorable matchup leaves you down a body for the privilege of starting a brawl. This trades that symmetry for a one-sided exchange, where only the opposing creature takes damage and only yours gets the temporary buff. The +1/+0 is the deciding wrinkle: it nudges your attacker past the toughness it would otherwise stall against, so a creature that would have merely traded now kills clean. The genre's standing cost has always been that you need a creature already in play to point at, which keeps it from being raw removal and ties it to a board that green wants to develop anyway. What sets this apart from a fight spell is that it functions as conditional removal rather than a coin flip; it cares only about your power against their toughness, not the reverse, so it is at its best aimed by a fattie at something fragile and at its worst stranded when you have nothing on the table. The single point of pump is small enough that the spell still respects color identity (green does not get to erase anything at any size), but precise enough to win the specific fights green builds its creatures to win.