Paintball Gun

The Painter has to die and you cannot hit him yourself, so you have to arrange an accident. Lava, a boulder, a trap, a hostile enemy, or something explosive placed at his feet all work. Building a small trap room next to your town is the usual answer, and the same setup pays off for every other NPC drop you want later.

Three shots come out per click, and they lob rather than fly flat, with a slight wobble in the air. Up close that hardly matters. Past half a screen you will start missing moving targets. It crits far more often than a normal weapon, and it costs nothing at all to fire, which is the real reason to keep it early.

It holds up against the Minishark on sustained damage while never touching your ammo supply, which matters a lot before money stops being tight. The Minishark is more accurate at range and holds fire on its own. Both drop off hard against armored enemies for the same reason, so whatever armor penetration you can find helps either one.

Hits recolor most slimes. It is purely visual, it does not change what they are, and it wears off when they touch a painted block or take another shot. It does make a herd easy to track across a screen, which is the closest thing to a use it has.