Flower of Frost

Fired into open air this is an unremarkable wand. Fired down a tunnel or into an enclosed arena it keeps rebounding off every surface it touches, and each rebound is another chance to catch whatever is in the room. It climbs a little on each bounce and sinks slowly, so it lingers around head height instead of rolling along the floor.

Platforms count, which turns an arena floored with them into a pinball table.

Early Hardmode is the window. Ice Mimics can be farmed on demand, so getting one is a decision rather than luck, and it beats most of what else is available at that stage. Frostbite adds a slow drain that suits the drawn out fights of that period. It cannot pierce, so a crowd absorbs one ball at a time, though the bouncing partly covers for that in tight spaces.

This is the Hardmode answer to the Flower of Fire, and both are nodding at the Mario power ups. The frost version is closer to the source, since the ice balls in those games bounce as well.