Bezoar

Poison is not dangerous on its own, it is annoying: it ticks away at you and blocks your health regeneration while you are trying to get out of a fight. Hornets and toxic sludges apply it constantly, so an Underground Jungle trip without immunity is a slow bleed. With it equipped, the whole category stops mattering.

Acid Venom is the harder version of the same idea and this does nothing about it. That is worth knowing before you head back to the jungle in hardmode expecting the same protection.

It is a situational accessory. Leave it in your inventory or a vanity slot and swap it in for the trips where poison is the problem, since almost anything else is worth more the rest of the time. It also converts to and from the Adhesive Bandage in Shimmer, so one drop covers two different immunities depending on what you are about to fight.