We present results from a Chandra observation of the cluster gas associated with the FR II radio galaxy 3C 438 .
This radio galaxy is embedded within a massive cluster with gas temperature \sim 17 keV and bolometric luminosity of 6 \times 10 ^ { 45 } ergs s ^ { -1 } .
It is unclear if this high temperature represents the gravitational mass of the cluster , or if this is an already high ( \sim 11 keV ) temperature cluster that has been heated transiently .
We detect a surface brightness discontinuity in the gas that extends \sim 600 kpc through the cluster .
The radio galaxy 3C 438 is too small ( \sim 110 kpc across ) and too weak to have created this large disturbance in the gas .
The discontinuity must be the result of either an extremely powerful nuclear outburst or the major merger of two massive clusters .
If the observed features are the result of a nuclear outburst , it must be from an earlier epoch of unusually energetic nuclear activity .
However , the energy required ( \sim 10 ^ { 63 } ergs ) to move the gas on the observed spatial scales strongly supports the merger hypothesis .
In either scenario , this is one of the most extreme events in the local Universe .