Biosynthic Burst

Green's instant-speed interventions usually carry a tax: fight spells demand your creature win an exchange it did not pick, and raw pump can still leave the boosted body dead to a bigger blocker or to instant-speed removal. This one strips most of that fragility out by stacking a package that turns a single creature into a one-turn tank. Indestructibility means the creature walks into anything and comes out intact, since both combat damage and destroy effects slide off; reach lets a grounded body ambush a flier; trample pushes the counter-boosted power through to face. The untap clause is the sharpest wrinkle, because it reads as an afterthought until you use it on a creature that has already attacked: swing on your turn, then flash this in during your opponent's, and the tapped-out attacker stands back up as a beefed-up blocker, effectively attacking and defending across a full turn cycle. The +1/+1 counter is the permanent residue, the one piece that survives past end of turn, so a trick that would otherwise be pure tempo leaves the board slightly upgraded even after the temporary abilities wear off. The single-target dependence is what pins the whole thing down: point it at a creature and let the opponent respond with removal, and the spell fizzles with the counter never landing. For two mana, green gets an ambush that refuses to trade back, but only when the target is still there to receive it.