Frostburn Arrows are arrows crafted using Ice Torches. They have a chance to inflict the "Frostburn" debuff and emit blue light when shot. However, unlike Flaming Arrows, water cannot extinguish their fire: arrows shot into water will continue to emit light when traveling through them and will drop as Frostburn Arrows instead of Wooden Arrows, and enemies who catch fire from those arrows will not have the fire extinguished when entering water.
Their break chance seems to be the same as Flaming Arrows.
Frostburn Arrows have the same sprite as Flaming Arrows, Spectral Arrows, and Cursed Arrows, only with a different color.