The pearl can absorb and store all types of poisons. After absorbing enough energy, it can then be used to attack others with its extremely potent poison.
While in the Void Illusionary Divine Palace, Nie Li uses it to absorb the venom of the Blackwater Venom Spiders. After using some Inscription Patterns to form a connection to the pearl's spiritual nature, he was able to command it to attack the spiders. The poison held in the pearl was so strong that it could even kill the highly venomous spiders.