The Boy's Axe is an axe-type rangedweapon which deals damage and roots the victim on hit, and can be recalled for additional damage. This item is exclusive to the Rise of the Giant DLC.
Can be used as a main weapon or as a secondary in combination with any other weapon, including the ones that require rooting, such as Nutcracker or Baseball Bat.
Both of these weapons can be used in combination with Heart of Ice for a constant cooldown reduction from attacking rooted enemies.
Deals approximately 230 Dps (2 throws + 1 recall) when used with Ammo mutation.
Trivia
Given the name and item description, this is probably a reference to God of War (2018).
The reference is that the main character Kratos keeps calling his son Atreus “Boy”, which has turned into a meme.
The axe's design and function are also reminiscent of Kratos’ Leviathan Axe in the God of War game, except it actually freezes enemies instead of simply rooting them in place.