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.
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.