The concept 

You've cured hundreds of Zombie Villagers. You've fed them Golden Apples, splashed Weakness on them, built iron bar cages and surrounded them with beds like some kind of overprotective parent. You've watched them shake and shudder and slowly turn back into the annoying little trading machines they were always meant to be.

But did you ever think... what if you went the other way?

Introducing "Villager Zombification"

Ever wanted to turn a villager into a zombie villager on your own terms? This addon adds the "Zombified Apple" — a craftable item that lets you kickstart the zombification process manually, no zombie or a specific difficulty required.

How to craft the zombified apple?

Simple enough just like a Golden apple recipe but with rotten flesh instead of gold

How it works:

Give a villager the "Strength" effect, then use a Zombified Apple on them. They'll be inflicted with Weakness and begin a slow conversion over the next 3–5 minutes. Surround them with "iron bars and a bed" to speed up the process — just like a proper curing setup, but in reverse.

Once the timer runs out, the villager turns into a zombie villager, ready to be cured with a Golden Apple and Weakness for your cheap trades.

After zombifying a villager his trades will NOT change mean you can zombify any villager without worrying about his trades being changed 

Eat it yourself?

 Go ahead — but expect Hunger and Weakness as a consequence.

No setup required.

 the addon uses /event command but this command only work in hard difficulty so it changes the difficulty to hard then The addon automatically handles any difficulty requirements behind the scenes and restores your world's difficulty exactly as it was. Works on Peaceful, Easy, Normal, and Hard worlds without any configuration.

Features:

- Craftable Zombified Apple item

- Manual villager-to-zombie conversion

- Conversion speed boosted by iron bars and beds nearby

- Zero difficulty side effects — fully automatic

-Survival friendly (item is consumed on use) 

- fully optimized no annoying whachdogs