Party Bullet

Everything that goes into these comes out of NPC shops, so you restock without leaving town and without farming a single enemy. Buy in bulk and ammo stops being something you think about. They also hit harder than any other bullet available before Hardmode, so for that whole stretch of a run there is not much reason to load anything else.

The catch is that you cannot craft them before Hardmode. Until then the only source is a Pigronata, which the Party Girl sells during a Party, and only some of the smashes drop bullets at all.

Fire a burst straight up and watch where the confetti comes back down. If it stops and falls in a flat band partway up the sky instead of drifting all the way to the ground, something solid is up there. It is a cheap way to sweep for floating islands without flying up to check.

Only two things in the game make an enemy burst into confetti, this and the Flask of Party, and both come out of the same pinata. The bullets glow pink in flight and stay fully lit in the dark.