Putrid Scent

The offense is the part you notice solo. The reduced aggro barely registers when you are the only target in the world. In co-op it changes the shape of a fight: run a glass cannon build while a friend in heavy armor wears gear that pulls attention, and enemies commit to the tank while you free-fire from behind.

Straight out of the Wall of Flesh, this is one of the strongest generic offense accessories available with no grinding beyond a single Corrupt Mimic. It roughly matches an Avenger Emblem in average output and arrives much earlier. Summoners get less from it, since minion hits ignore critical strike chance entirely.

Every accessory it feeds into throws away the offense and keeps only the aggro effect. That is a real downgrade in single player, and the Arcane Flower is the worst case because it gives nothing back. If your world rolled the other evil, Shimmer will trade it for Flesh Knuckles and back again.