The Rotted Fork

This is one of the longest melee options in the game before hardmode, and the burst at the tip stretches the hitbox out past where the sprite ends. You poke from outside the range of most early enemies and never get touched. Melee speed bonuses do more here than they do elsewhere, because a faster thrust also travels further.

It comes out of Crimson Hearts, and the boss on the other side of those orbs is exactly what it is best at. The Creepers in the first phase line themselves up in front of you and the spear clears them without you moving your feet. In the second phase the knockback keeps the brain from settling on top of you. If one turns up before you fight it, use it.

Prefixes attach to the front of the entire name, so you end up carrying a Keen The Rotted Fork. Every item beginning with The has this problem. There is also no Corruption equivalent, so a Corruption world simply goes without a spear at this point in the run.