new mob or structure ideas for my cursed forest biome

Idea: A mob named Dark Witch, what makes it different from a normal witch? It flies on a cloud (the cloud is part of it's model) always looking at the player and from time to time just gives the player a random negative effect instantly without a potion. They drop dark essence that can be used to make the Debuff Staff that inflicts a random negative effect on the targeted entity (though it has a cooldown)