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Every 50th kill of this enemy drops Mushi Ladybug Banner.where it lives and why it hurts
It comes with glowing mushroom ground. Before hardmode it only appears in surface mushroom patches, which is the trap, because the surface patch is usually one you planted yourself to get the Truffle to move in. Once hardmode starts it spawns in underground mushroom biomes as well, so the cave version stops being the safe one.
For something you meet before hardmode it is fast, hits hard, and can leave the ground for short hops, so backing onto a ledge and plinking at it does not work the way it does on the rest of the surface. Wall your mushroom housing off from open ground before you move anyone in, or you will come home to a dead NPC.
the name
It reads as mushroom at a glance, and mushi is also the Japanese word for insect.