It is a trap that attacks enemies,The cauldron does not deal direct damage but rather affects an area with poison and those affected receive continuous damage for a time,it is used by Johan in DIVINE DEFENSE.
Reference image by Olga komochkova (https://www.artstation.com/kus_kus)

Reference image by Olga komochkova (https://www.artstation.com/kus_kus)