Rat Lab Mutation Gun: Scientist Priority and Preparation
Prioritize the Mutation Gun when tools are contested, check Index colours before experiments, and review its September 2026 R$299 gamepass listing.
Quick answer
The Mutation Gun is the Scientist's signature mutation tool in Rat Lab. Prioritize it when tools are contested, and prepare for experiment chains by checking your target mutation and colour meanings in the Mutation Index. Its September 2026 gamepass listing priced it at R$299.
- Who uses it: mutation-focused Scientists. It is ranked as the “Science identity” tool — the item that defines the role, in contrast to emergency defenses like guns or snipers.
- What it changes: from the Lab Rat side, the mutation gun and Index colours change a tagged rat's effective HP and options — a Scientist's tag alters what the subject can do and how durable it is.
- How to use it well: pair the gun with Mutation Index colour literacy, keep ammo discipline, and expect counterplay — good rat revenge targets an isolated scientist mid-mutation.
Open the Mutation Index before long experiment chains so you know your target mutation, and confirm colour meanings before tagging allies or rats. When using the gun, conserve ammo rather than spraying.
How the Mutation Gun fits the Scientist experiment loop
Roadmap
- 1
Spawn and claim a workspace
Know which rooms are still powered or usable after the latest patch.
- 2
Check the Index UI
Confirm colour meanings before you tag allies or rats incorrectly.
- 3
Unlock tools in-session
Mutation Gun first if contested; Hazmat if the wing is toxic or unstable.
- Take the Mutation Gun first if it is contested
- Pick up Hazmat if the wing is toxic or unstable
- 4
Read the breach
If Lab Rats are mid three-stage escape, decide contain vs ignore based on your objective timer.
- 5
Respect Security lanes
Call positions; do not steal their net kills if you still need a living subject.
- 6
Extract value before death
A dead scientist with zero Index progress wasted the join.
Loadout order under session resets: decide your goal before spawn (science), prioritize the Mutation Gun when tools are contested, add one survivability piece (vest, armour, or Hazmat), and only then greed sniper or luxury guns.
Science-lens tier standing and the Mutation Gun tool note
Tips
S / A — Mutation Gun
Your job tool (Scientists, Mutations). Use ammo carefully rather than spraying. Pair it with Index colour literacy, and never sell Index colours as promo codes.
A — Hazmat Suit
Take it when wings are unsafe; otherwise it sits at B.
A — Armour
Against bite rushes.
B — Guns / sniper
Emergency defense, not identity.
Letters move with patches
Tier standings are goal-relative and patch-sensitive, not absolute power claims. Patches since the 30 July 2026 launch and the mid-September 2026 Forever / Mutation Codes pass updates can nudge the letters.
Mutation Gun and the Mutation Index workflow
The gun is meant to be used with the Mutation Index, not instead of it. Colour and mutation codes track specimens — they are not promo gift codes you can redeem anywhere. Know both ends of the tool: when a Scientist tags you as a Lab Rat, the gun's colour statuses and Index colours change your effective HP and options, so find out what a colour means the moment it lands on you.
Mechanic flow
- 1
Open the Index first
Open the Index before long experiment chains so you know your target mutation.
- 2
Log colour codes privately
Log colour codes in a personal note if you are collecting — they are still not promo codes.
- 3
Weigh All Mutation Codes (R$2499)
Consider it only if Index completion is your main reason to play; it is expensive compared to Hazmat (R$249) or Mutation Gun (R$299).
- 4
Re-check Updates
Re-check Updates when Evil Science patches mutation behavior.
Gamepass listing and price
Comparison
| Attribute | Detail |
|---|---|
| Access path | Paid store gamepass. The store's paid options also include Hazmat Suit (R$249), Armored Guard (R$249), MG (R$299), Sniper (R$399), Stronger Bite (R$75), Stronger Leash (R$99), plus Forever unlocks for tools. |
| Price | R$299 in the September 2026 gamepass catalog. |
| Catalog description | “Mutation gameplay tool” — also described as a “direct mutation gameplay tool.” |
| Intended user | Mutation-focused scientists; it is a scientist-relevant paid option. |
| Value framing | Comfort, not requirements. Hazmat Suit (R$249) and Mutation Gun (R$299) are the common paid quality-of-life pair — the gun is not a requirement for the For Science or New Specimen badges. |
| Buying advice | Buy only after you understand the free timer path. |
The September 2026 catalog lists the Mutation Gun gamepass at R$299 for mutation-focused Scientists. Check the live in-game store price before buying.
Practical discipline and counterplay around the Mutation Gun
Mistakes to avoid
- Problem
- Spraying the Mutation Gun like a combat weapon
- Fix
- Ammo discipline beats spray — it is a precision job tool, not a sprayer.
- Problem
- Standing still while tagging
- Fix
- Rats bring bite and vest buffers (+50 HP). Use doors, elevation, and Security help.
- Problem
- Finishing a mutation cast in the spot where you fired
- Fix
- Relocate after loud gunfire.
- Problem
- Taking first contact yourself
- Fix
- Let Security take first contact when they exist; your job is not to out-duel shotguns.
- Problem
- Fighting through mid-lab pileups
- Fix
- They are where scientists die most — prioritize survival gear, then Index ticks, then ego plays.
- Problem
- A rat is clearly finishing stage three
- Fix
- Decide whether your experiment still needs them alive before committing more tags.
- Problem
- Casting alone in open labs
- Fix
- Expect revenge targeting — good rat revenge goes after an isolated scientist mid-mutation.
Prices and tier letters here are dated to the mid-September 2026 update wave. Check live store prices before making a purchase.