User blog comment:SilverHexxitFights/Which is Terraria's Hardest Boss?/@comment-24169653-20131116180728/@comment-24165453-20131117231230

This.

Which makes the Pumpking Moon event all the more interesting because you don’t just have to survive (no challenge for a caster with a Spectre Armor) but actually deal enough damage before dawn breaks so you can get to the higher waves.