Corruption is a voodoo hex used exclusively by Jolly Roger during Invasions.
It is a very powerful form of Wither that can inflict up to 1,000+ damage on nearby pirates. The amount of damage done depends on the number of pirates defending against the invasion. The more pirates present, the higher the damage will be. Corruption may also deliver a special duration condition that causes up to 100 damage every 3 seconds, lasting for about 30 seconds. This can deal as much as 1,000 damage total over time, which can be enough to finish low-level pirates who managed to survive the initial attack.