Witch addition

Just like with the rare occurrence of a "jockey" mob, Example: (Spider Jockey)

Maybe this could be a "Witch Jockey"?

There would be an equal chance that there would be a special witch would spawn, this one would be riding a phantom, or broom (so it would be a sky mob). It wouldn't be as fast as throwing potions, it would not have the ability to use healing potions, or poison potions, only Slowness potions. But it would be able to use speed potions, which would make it a little more difficult to hit, but would also be a balance for not being able to heal itself. 

The reason it would only use slowness potions is more of a "support" role, as it would put you in a bad position if surrounded by mobs. 

This would be a rare spawn (like the spider jockey), and would make the night sky a little more alive, and deadly. Making it either that much more important to sleep, or that much more fun to find one of these mobs. 

There could even be an achievement (They came from, above), a reference to "They came from, behind" from other media.