Description
This carpenter's hammer was never designed to work as an actual tool. Rather, it is an implement meant to sap someone's strength when clobbering them.
Source
The item can be looted from the following NPCs 
:
See Also
Repair
Legendary items cannot be repaired.
Dismantle
The The Mallet can be dismantled using the 
Dismantling Bench to recover the following materials:
- 6
Eldarium 1
For slightly more materials, you can use the 
Improved Dismantling Bench:
- 8 Eldarium 1
1 If this item is dismantled on the Exiled Lands, you get the same amount of 
Star Metal Bars instead of the displayed amount of 
Eldarium or 
Decaying Eldarium.