Coming from the world of tomorrow, the Atomic Calamity is here to protect the west from the communists! His greatest superpower is the ability to create nuclear explosions of any size, at will! As it happens, this is also his only superpower, so whenever the Atomic Calamity appears, there is always a risk of collateral damage. Even when helping with trivial problems such as saving cats from tall trees, the Atomic Calamity must often resort to nuclear explosions of appropriate size, bringing the tree down to save the cat. Unfortunately, this often causes nuclear fallout, giving the cat cancer from radiation and eventually killing it.
God bless the Atomic Calamity!
EDIT: Fixed some things. Original version here.