Diamond Staff

The gem staves are the pre-Hardmode magic ladder and this is the last rung. The bolt punches through one body and stops, so it is a single target tool with a little cleanup attached, not a crowd clearer. Against the worm bosses that limitation barely registers, since every segment counts as its own target.

The bolts slip through the angled face of a slope or half block instead of stopping on it. Build a firing slit out of slopes and you can shoot out while most things coming back at you hit the wall. Every other gem staff does the same.

Diamonds are scarce enough that plenty of runs never bother, and the earlier gem staves feel close enough that the upgrade is rarely urgent. Once the jungle or the dungeon hands you a real magic weapon, the whole line retires at once.