Vartox's axe was an axe that belonged to Vartox. It was powered by a self-generating atomic charge, reaching temperatures up to 2,500 degrees.
Vartox used the axe to fight Supergirl on two different occasions, the first of which he was able to cut her arm. In the process, he left a piece of it behind for the D.E.O. to track due to its unique nuclear thumbprint. The axe was later destroyed when Kara used her heat vision to overheat the metal and made it explode, injuring Vartox, who then used a shard of the axe to stab and kill himself.