Quagmire Weapon

You gain a +2 bonus to attack and damage rolls
made with this magic weapon.
While you're holding the hammer, you can
traverse any swamp as if it were normal terrain.
This hammer has 10 charges and regains 1d6+4
expended charges each day at dawn. As an action,
you can expend any amount of charges. For each
you transform 5ft of terrain in a knee deep swamp.
This area is considered difficult terrain.