Dark Lance

Spears trade width for depth, and this one has more depth than anything else you can hold before Hardmode. You stand back, poke, and let the tip do the work, which suits fights where closing the distance is the thing that kills you. The burst at the end adds a little reach past where the sprite looks like it stops.

Melee speed bonuses do something unusual here. They lengthen the thrust as well as quickening it, so claws or a well fed buff literally extend how far you can hit from.

The burn it applies keeps ticking after you back off. That matters far more against one tough target than against a crowd, since a spear only covers a single line at a time.

It is a reasonable pick for that fight. Reach lets you work on the eyes while staying ahead of the mouth. If you have managed to put the Night's Edge together, take that instead and keep this as the backup.