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Core Keeper • Boss Guide

Ivy the Poisonous Mass

Biome: Azeos' Wilderness HP: High Last updated: 2026-02-28
← All bosses Best food tier lists Auto golden crop farm

How to summon / find

Found naturally in the Wilderness on a poison slime sigil.

Recommended food focus

Pick one main meal plan that fits this fight, then keep one backup plan (survival or extra damage).

Ranged Damage Poison Resistance.

Prep checklist

Bring these before you start—this is the fastest “stop dying” layer.

  • ✓ Poison Immunity (Food/Gear)
  • ✓ Ranged Weapon
  • ✓ Swiftness Potion
  • ✓ Clear the area

Deadly attacks to dodge

If you learn only 3 things, learn these. They cause most wipes.

Poison Mortar
Fires poison globs into the air that land on the player.
How to dodge: Keep moving; don't stand in the impact circles.
Toxic Leap
Similar to Glurch but leaves poison trails.
How to dodge: Dodge the shadow and avoid the trail.

Core mechanics

Giant poison slime (~600 tiles from Core). Shoots poison mortars from the sky.

Win strategy

Use poison immunity food or gear. Stay mobile to avoid the mortar impact zones.

Best food for this boss

Pick 1 meal from the primary plan. If you’re dying, switch to the backup plan instead of forcing DPS.

View all tier lists →

Primary plan

Top pick
Pinegrapple + Iron Tail
  • • ranged damage: +22%
  • • crit chance: +13%
Tip: avoid overlapping buffs—pick a focused combo.
Top pick
Iron Tail + Desert Sunfish
  • • crit chance: +13%
  • • ranged damage: +22%
Tip: avoid overlapping buffs—pick a focused combo.
Top pick
Pinegrapple + Emerald Feather Fish
  • • ranged damage: +22%
  • • crit chance: +7%
Tip: avoid overlapping buffs—pick a focused combo.
Top pick
Emerald Feather Fish + Desert Sunfish
  • • crit chance: +7%
  • • ranged damage: +22%
Tip: avoid overlapping buffs—pick a focused combo.

Common mistakes

Read this if you keep failing. It’s usually one of these.

  • • No poison immunity
  • • Getting stuck in poison trails
  • • Low mobility

Key drops

What you’re actually here for—and what it’s used for.

Ivy's Ring
Increases poison damage.
Poison Slime Oil
Summons the Poison Merchant.

Need golden ingredients faster?

Farming by hand slows down progression. Automate golden crops to power your best food buffs.

Auto-farm guide →

Related

FAQ

What food should I bring to Ivy the Poisonous Mass?
Bring 1 main plan (damage or survival) plus 1 backup plan. Avoid overlapping buffs—buffs of the same type usually get overwritten by the last meal you eat.
Do food buffs stack in Core Keeper?
Not usually. Buffs of the same type tend to overwrite, so pick a focused combo instead of stacking many similar meals.
How do I farm ingredients faster?
Automate crops. A golden crop farm is the fastest way to remove the cooking grind for endgame buffs.