Capacitors are known to explode when charged too much. This means that if a highly charged planet comes in contact with a smaller planet, the bigger planet may cause the smaller one to explode.
The effect would be like connecting a fully charged industrial capacitor to a much smaller capacitor.
Again, we are struck by the enormity of such an event. It seems impossible. However, the laws of electricity scale perfectly. What is true for capacitors in laboratories on Earth is also true for planet size capacitors in space. Charged too much, they explode.
Not only is such an event a theoretical possibility. There is evidence to suggest that it has happened in our own solar system, quite possibly due to the same rogue planet that scarred Mars and zapped the Grand Canyon into the crust of our planet.