User blog comment:Oddgasm/Osmeria, the Ethereal Despot/@comment-7709681-20150902000327/@comment-26869721-20150902072354

My bad, that was indeed a scaling passive that could apply on the 3rd consecutive hit on champion (consecutive just like Vayne's W, means that if you change your target, it resets it).

I don't think it is actually unhealthy for several reason. There are items and skills that instantaneously make the target gain max HP, so why not the opposite ? It's only a matter of seconds, after all (I'm thinking about Lulu's R, Sterak's passive, Gnar's passive etc).

Besides, the reduction is applied only by Osmeria herself, which isn't actually that strong.

Moreover, when you have 1000/1000 HP, taking 200 dmg would reduce your HP to 800/1000 HP (800/800 HP if against Osmeria) ; in this case, only your current HP matter, unless you're based on sustain.

Shields would still work and Lulu's R would still work.