-= Examples =-

Hood of the Cursed is like BK Cowl, but has no status weaknesses (maybe even some extra resistances), instead in every map, it will spawn an additional special Phantom that targets specifically you.
Maybe there is also a Mantle of the Cursed, so you would get two Phantoms trailing you, if you equip both.

Crown of Darkness is like Chaos Cowl, but again it has no status weaknesses, but this time a Grimalkin will be after you on every map!
If you also wear Shadowmail, it will be 2 Grimalkins being enabled by it's aura of darkness to leave the Candlestick Keep and hunt you down!

Soulless Suit will have those exploding Souls spawn around you. It gives you amazing bonus, like CTR high, MSI high and damage bonus high, but now you gotta be careful not to get hit by souls wherever you go.
Since there are different types of souls in the game already, it could have variants, e.g. Soulless Firesuit would have extra fire resist, but spawns Frozen Souls, etc..

Imagine the chaos/fun if a whole party equips these and you have 8 basically unbeatable extra monsters coming after the party, all of the time, but also they can absolutely shred through all other monsters.