Happy Grenade

It bursts into confetti and hits for half what a plain Grenade does, while costing several times as much per throw. Two of them add up to one real grenade and still cost many times more than one, so no arithmetic rescues this as a serious explosive. Buy them for parties, arena decoration and the noise.

The Party Girl will not sell you any until you already have one on you, and the only way to get that first one is to kill her. She does not drop them every time either, so plan on doing it more than once. Once you are carrying a stack the line appears in her shop and you can buy freely. Spend them all and the line vanishes again, so hold one back if you intend to restock later.

You cannot damage a town NPC yourself, so it takes an outside source. The quickest options are the Flymeal or the Classy Cane, which handle it in one use. Failing that: drop her down a shaft, drown her, roll a boulder or a rolling cactus into her, set off a Land Mine or an Explosive Bunny, or leave her outdoors while something hostile is around. Lava works and is the worst choice available, because a pool deep enough to finish her also burns up the drop before it floats to the surface.