AS + HP + mana on a tanky item
stats:
625 hp
35 to 40 AS
250mana
no cdr
might be cool to have a passive similar to
so when a tank triggers ultimate they can get faster cooldowns.
that or be able to run faster (only away from or only towards direction of own fountain) after auto attacking a champion. when fleeing not chasing, maybe another trigger could be as hp gets lower gain ms. happens once every 40 seconds would work a bit like the rageblade of old season 3 or so.
feel free to discuss any ideas of yours for possible passive/active.

why is this item needed?
is pretty niche and meh, while
is very expensive and mostly offensive/ not very tanky
is for melee only, maybe this item could also be melee only, or get a tiny buff on melees.
a little like how
gives more ms on melees. but the passive on this proposed item would even further benefit melees since phage pretty much gives equal value when used on range.
which is pretty unique to them.
's passive would factor as defensive value too.
to sit on in the mean time.
parabolic curves are what allows for great fine tuning. But also have a cap so items do not scale too much either.
players needn't know the formula, as long as it works that's what matters (if they must know they can always read wikia).