AP Bruiser Equivalent to Black Cleaver?

Item could combine and

Stats: -50 AP -50 Armor -200 HP -20% CDR

This could work nicely on jax: . would also be half decent on yorick , as his E heals him based off of magic damage. The ap wouldn't be that bad its only 50 and his w has a 100% ap ratio. and since its armor it would pair well with spirit visage. plus manamune and sunfire cape or righteous glory. The CDR also helps him use q more often making it sort of hybrid.

Unique Active: It would be similar to Nasus's spirit fire. In that you mark a target 175-radius area. and would reduce their resistance per second while they stand in it, by -3.5% magic resist per half a second (max 3.5 sec).
Debuff would last for another 3 second when outside the circle. and would pick up where left off if they reenter before the debuff ends. Would only reduce an enemy's resistances towards you. Since there is already abysal scepter. It would not do any damage however. or perhaps it could have a slow burn to it as well.

the active would have a fairly short cooldown too like 20 seconds sort of like hydra active.

there is also some counter play to it as people can try and stand outside of it or try to kite to bring to fight away from wherever you placed it.