Our Halloween quest to determine the spookiest song in rock history has advanced into its third week.

After our round two "Evil Eight" battles , we're down to the "Frightful Four." Only the most fiendish duo can move onto the finals.

You can vote once an hour in the two brackets posted below.

Round three voting ends on Thursday, Oct. 23 at 11:59PM EST, with the finals launching the next morning. The spookiest rock song of all time will be crowned on Halloween.

Iron Maiden 's "The Number of the Beast" reached the semifinals by beating out another devilish song, the Rolling Stones ' "Sympathy for the Devil" in week one by a margin of 54% to 46%. "Beast" then went on to defeat Alice Cooper 's "Black Widow" 64% to 36%.

Maiden now go up against the mighty Metallica and "Enter S

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