Editor’s note
The Index is the most overlooked progression system. Each filled slot gives permanent luck — it compounds with rebirth multipliers, making it one of the highest-value long-term investments in the game.
The Slime Desk · 2026-05-18
Home · Index Rewards
Collection system · permanent rewards
Index Rewards
The Index tracks every unique slime you’ve collected across all variant types. Hitting milestones grants permanent luck bonuses, coins, Goop, and crafting recipe unlocks. It’s the long game — and it compounds with everything else.
5Index types
PermanentReward type
Luck + CoinsKey rewards
Apr 25System added
Sourced from Fandom + community dataUpdated July 2026
Index Categories
▦
Base Index
Track unique slimes collected. Each slot filled grants a permanent luck bonus. Completing milestone thresholds unlocks coins, Goop, and crafting recipes.
◆
Big Index
Track Big variants obtained. Big slimes are uncommon mutations with higher stats. Completing Big milestones grants extra luck multipliers.
★
Shiny Index
Track Shiny variants. Shiny slimes are rare cosmetic mutations. Index milestones reward food items and Goop.
▲
Huge Index
Track Huge variants. The rarest standard mutation. Huge Index milestones grant significant luck boosts and exclusive recipes.
◇
Inverted Index
Track Inverted variants. Ultra-rare mutations introduced in the Huge Update. Completing Inverted milestones grants the largest luck bonuses.
Milestone Rewards
Exact reward values may vary between game patches. These thresholds are sourced from community data and the Fandom wiki.
| Category | Threshold | Reward |
|---|---|---|
| Base | 10 unique slimes | Coins bonus + permanent luck increase |
| Base | 25 unique slimes | Goop bonus + crafting recipe unlock |
| Base | 50 unique slimes | Significant luck multiplier increase |
| Base | 100 unique slimes | Major milestone — large permanent luck bonus |
| Big | 5 Big slimes | Luck multiplier bonus |
| Big | 10 Big slimes | Food items + Goop |
| Huge | 3 Huge slimes | Large luck bonus + exclusive recipe |
| Shiny | 5 Shiny slimes | Food items + coins |
| Inverted | 1 Inverted slime | Significant luck bonus |
What to chase first
Finish cheap base slots before variant hunting
Early Index progress comes from breadth, not luck spikes. Roll in each unlocked zone, fill missing base entries, and claim the low-threshold rewards before spending boosts on Big, Huge, Shiny, or Inverted variants.
Keep duplicates until recipes are checked
Some duplicate slimes are crafting ingredients, and deleting them can slow a recipe unlock later. Before cleaning your backpack, compare duplicates against the crafting recipes and keep anything tied to a scroll.
Treat exact payouts as patch-sensitive
The categories and milestone shape are stable, but exact reward amounts are community-sourced. The safest check is still the in-game Index panel after a major patch, especially around recipe unlocks and permanent luck bonuses.
Tips for Completion
- 01
Roll in every zone
Each zone has unique slimes. Push to new zones to fill Index slots faster rather than grinding one zone for rarities.
- 02
Keep duplicates for crafting
Crafting recipes require specific slimes as ingredients. Don't delete duplicates until you've checked recipe requirements.
- 03
Stack luck for mutation variants
Big, Shiny, Huge, and Inverted variants need luck to appear. Use Luck Potions and rebirth multipliers during active sessions.
- 04
Check Index progress regularly
Open the Index panel to see which slimes you're missing. Target specific zones for missing entries.
- 05
XP Transfer Machine
Introduced in the INDEX Update (April 25). Transfer surplus slime XP between slimes to level up your team faster.
Index FAQ
- What is the Index in Slime RNG?
- The Index is a collection tracker that records every unique slime you've obtained. Filling slots and reaching milestones grants permanent rewards like luck bonuses, coins, Goop, and crafting recipes.
- Which Index rewards should I prioritize first?
- Fill cheap Base Index slots first because every new slime counts and the rewards compound early. Chase Big, Huge, Shiny, and Inverted milestones after you have stable zone access, Auto-Roll, and enough luck to make mutation hunting realistic.
- Do Index rewards stack with rebirth multipliers?
- Yes. Permanent luck bonuses from the Index stack multiplicatively with rebirth luck multipliers, making Index completion a powerful long-term progression path.
- What is the XP Transfer Machine?
- Added in the INDEX Update (April 25, 2026), the XP Transfer Machine lets you move surplus XP from high-level slimes to low-level ones. This helps level up new slimes faster without grinding.
- Do I lose Index progress when I rebirth?
- No. Index progress is permanent and carries across rebirths. This is one of the reasons Index completion is a high-priority long-term goal.
- Are exact Index reward values verified?
- Exact values are currently community-sourced and can move after patches. Use the milestone list as a planning map, not a guaranteed payout table, and check the in-game Index panel before spending rare duplicates.