Nail

Nailheads drop it during a Solar Eclipse, and those only start showing up in the event after Plantera has fallen, so this is a late pickup rather than something you can rush toward. The gun always arrives with a healthy stock of Nails. Once you own it, both the Merchant and the Arms Dealer will sell more, though only while the gun is sitting in your inventory, so parking it in storage quietly removes your ability to restock.

The nail that leaves the barrel barely registers. It sticks to whatever it lands in, enemy or wall, and detonates a moment later, and effectively all of the weapon's output lives in that explosion. The blast covers a generous square around the point of impact, so a nail buried in the floor still catches everything standing near it. Nails also travel perfectly flat for a long stretch before gravity takes over and they start arcing like arrows, which means close and mid range shots need no lead at all.

The wait changes what the gun is good at. Against anything that teleports or turns briefly untouchable, the nails ride along through all of it and go off anyway, so enemies that dodge out of hits cannot dodge these. Killing a target that is still bristling with them scatters the leftovers in random directions, where they stick to walls and other enemies and start counting down again, so a packed room takes itself apart. A nail whose block gets mined out simply hangs there until it is due. None of the explosions can hurt you, so firing into the ground at your own feet inside a crowd is a real tactic rather than a mistake. What it is bad at is small quick enemies, which tend to be somewhere else by the time the nail is ready.

It has no knockback of its own, so every modifier that touches knockback is off the table and Demonic is the practical ceiling. In player versus player the whole gimmick switches off: nails will not stick to another player and just deal their impact damage on contact, which makes it far weaker there than it looks.