Because the boomerang is one handed players can hold one in each hand. Unlike a normal boomerang this weapon will deal frost damage and leave a trail of frost for a few seconds that deals damage to enemies who touch it.
The Frozen Boomerang has a base power of 9 and a 0.6-second delay before you can throw the Frozen Boomerang again after catching it. Each segment of the frost trail has a base power of 3.
The Frozen Boomerang cannot be found anywhere in the universe. The only way to acquire one is to convert a normal Boomerang into a Frozen Boomerang, either by crafting it yourself using the blueprint - which appears where other generic Legendary items appear - or by having it crafted for you at Biggy's Reputable Weaponry.
When upgraded at a Weapon Upgrade Anvil to tier 6, the Frozen Boomerang's base power increases to 10.5, and the trail segment base power increases to 3.5. Additionally, the Frozen Boomerang's appearance changes to the one shown below.
Apart from the addition of a gold star to the name, no other changes occur as a result of the upgrade.