The Battle Spear is a melee Weapon in the Reign of Giants DLC exclusive to Wigfrid. It can only be crafted by Wigfrid, and she starts the game with it in her inventory. It requires 2 Twigs, 2 Flint, and 2 Gold Nugget to craft and is available to craft in the beginning of the game.
Also, in Don't Starve Together, Wigfrid is allowed to give both the Battle Helm and Battle Spear to other players, making her an important asset to the team. But she is the only one allowed to craft it. Thus, this would be a great alternative to the Spear in the early game.
When used by Wigfrid, the Battle Spear does slightly more damage than a Tentacle Spike used by another character, who does not deal additional damage.