Creature Reference Back to Creatures

Ion Slime

Small · Ooze · CR 5 · Unaligned

Source. Tome of Beasts 3

112 (15d6+60)

Ability Scores

Core attributes and their modifiers.

STR

DEX

CON

INT

-4

WIS

-3

CHA

-5

Overview

Category Monsters

Size Small

Type Ooze

Alignment Unaligned

XP 1800

Initiative Bonus +3

Movement

Walk 20 ft (6.1 m)

Swim 20 ft (6.1 m)

Climb 10 ft (3 m)

Crawl 10 ft (3 m)

Senses

Blindsight 60 ft (18.3 m)

Passive Perception 7

Skills

Perception -3

Resistances & Immunities

Damage Resistances

thunder

Damage Vulnerabilities

cold

Condition Immunities

blinded, charmed, deafened, exhaustion, frightened, prone

Traits

Amorphous

Move through space 1ft.+ wide with o squeezing.

Ionic Form

Whenever subjected to lightning it takes no damage and instead regains hp equal to lightning dealt. Its Supercharge then recharges. If it takes cold while supercharged it must roll a d6. On a 1 or 2 it loses the supercharged state.

Ooze Nature

Doesn’t require sleep.

Spider Climb

Difficult surfaces even ceilings no ability check.

Bonus Actions

Charged Motion

Dash or Dodge action.

Supercharge

Recharge 5–6

Gathers ambient electricity to supercharge itself for 3 rounds. While supercharged slime gains +2 bonus to its AC and it gains an additional action on each of its turns. At end of the third round if the slime hasn't used the Discharge action it suffers feedback taking 18 (4d8) force. Its supercharged state then ends.

About Ion Slime

Ion Slime is a small ooze with a Challenge Rating of 5. It has a unaligned alignment.

In combat, this creature maintains an Armor Class of 13 and possesses 112 hit points (derived from 15d6+60).

GM Tips: Using Ion Slime

2 tips available

When using Ion Slime in your D&D 5e campaign, consider these tactical approaches:

Aquatic Combat: This creature can swim at 20 ft. It has advantage in water environments. Consider fighting on land or using water-based spells against it.
Amorphous Movement: This creature can squeeze through spaces as small as 1 inch! Traditional barriers are ineffective. Use 'Wall of Force', 'Forcecage', or magical barriers to contain it.

Player Guide: Facing Ion Slime

2 strategies available

When your party encounters this creature, keep these strategies in mind:

Aquatic Combat Defense: This creature can swim at 20 ft! It has advantage in water. Fight on land if possible. Use 'Control Water' or drain water sources to limit its mobility.
Contain Amorphous Creature: This creature can squeeze through tiny spaces! Traditional barriers won't work. Use 'Wall of Force', 'Forcecage', or magical barriers. 'Create Bonfire' can block movement.

Encounter Building Calculator

Standard Party Encounter (4-5 characters):

This creature is a medium encounter for a party of 4 characters of level 5.

Solo Encounter:

A single character of level 7 (up to level 20) can face this creature in a medium to hard encounter.

Experience Point Thresholds:

Medium: 3,000 XP
Hard: 4,500 XP
Deadly: 6,000 XP

Based on D&D 5e Dungeon Master's Guide encounter building guidelines. CR roughly equals party level for medium encounters.

Frequently Asked Questions

What is the challenge rating of Ion Slime?: Ion Slime has a Challenge Rating of 5, making it appropriate for parties of level 5.0.
What type of creature is Ion Slime?: Ion Slime is a Small Ooze, which affects how certain spells and abilities interact with it.