How to obtain the Blade of the Headless Horseman in Terraria:

Prepare a Hard Mode anvil and collect enough raw materials.

Find the Pumpkin Moon Medal in the Mithril Anvil/Orichalcum Anvil production interface and craft it.

Use the Pumpkin Moon Medal to trigger a pumpkin event at night.

Defeat the Pumpkin King, and there is a chance of dropping the Headless Horseman's Blade.

If you don’t get the Headless Horseman’s Blade the first time, don’t worry, the Pumpkin Moon event will continue until dawn.

Continue to defeat the Pumpkin King, and there is a chance of dropping the Headless Horseman's Blade each time.

Please note that the probability of dropping the Headless Horseman's Blade is not high, so you need to be patient and challenge the Pumpkin King repeatedly. In addition, the item drop mechanism in the Terraria game may change due to version updates, so it is recommended to check the official game website or the player community for the latest and most accurate information.