Ominous Event where you fight THE Omen

A new boss called "The Omen" or something like that, which is a dark shape-shifting cloud with red eyes. It could be summoned by drinking an ominous bottle while already having the effect, or maybe some unique item that's made from other ominous event items. It would give you a minute to drink milk before it spawns. It would summon weaker mobs at first and stronger ones at the end, spawn arrows & potions above the player and directed towards the player, and get new moves when new ominous events are added. This would be a later game boss like the Wither, and could put a face to the ominous effect and omen. It's loot table would be a cherry picked mix of trial chamber and raid loot, and would include at least 1 new item, prefered two. (one item that's useful in someway like mobility, and another that serves as a trophy of sorts)

If you drink a third bottle--you start the Omen's ominous event, which gives it more health, more abilities (based off other ominous events), and a unique item/an improved variant of the usual item. (maybe an exclusive enchantment?)

I imagine it as a tall winged humanoid made of dark blue smog, but I think a sort of gas with two central eyes as it's main body would fit better. Maybe it could resemble the Vengeful Heart of Ender from Minecraft Dungeons? (I think that design is really cool, and the lore would go crazy)

I thought of this as a joke, but I actually think this could work! We need a new boss, and this could be a fun fight if done right!