is a very niche Item currently, The problem lies in the stats and the passive. It's only good against DOT but still crap in those situations. If you Increase its passive duration to 20 secs from 4 secs you have a item that ramps up during a fight against a spam mage(mages like cass) or dot mage instead of an item that does virtually nothing. A boost to stats could help as well.
late game 20 seconds can be 2 entire spell rotations for most mages...
20 is really excessive, maybe add 2-3 more seconds but not not 15. Many non spam, but still low CD mages easily can go through 2 or more full rotations. (champions like 
and 
)
I think people need to be careful about this item. It could single handedly make whole classes of mages unviable in the blink of an eye.
(Although I I never have to see another Cass again, I wouldn't feel too bad...)
Well adaptive helmet does feel a bit...situational...it only really is useless against champs with VERY low cd and Magic damage, such as teemo ryze and cass. i haven't seen it one single time in my games ever since it came out.
either buff the scaling, buff the duration or give an reduce to normal damage aswell, specifying it for spells of course.
