DoctorMcDerp
Plantera
Although considering what I said before comes down to luck, I would say the demon scythe. You are basically given a force field that makes you invulnerable against anything effected by knock back, and you can pick apart the destroyer due to it's piercing and the fact that it stays in one spot for a while before flying out. You can also use it to set down trap like attacks as the enemy will probably be attacking and swiping where you were 2 seconds ago, and the scythe will still be there. It is also very effective in crowd control.
The golden shower was close, considering you can use it into end game to debuff enemies and remove defense.
The golden shower was close, considering you can use it into end game to debuff enemies and remove defense.