Find Tachyon and ask about research
Look for Elsher Tachyon at the Itagura NPP entrance, near the other researchers. Her white coat, yellow uniform and small yellow backpack distinguish her from Manhattan. The kill-record dialogue opens your enemy information; choose the research conversation to request work.
The community NPC documentation sets Sergeant or higher as the requirement. A Private, Specialist or Corporal receives rejection dialogue. If you cannot get the sample task, check your rank before repeatedly trying the conversation.
Accept the first request before heading into the facility. Keep this page as a manual checklist; it does not read your in-game quest progress.
The three sample batches
Finish the active batch, return to Tachyon, then accept the next request. Do not assume kills made before accepting a batch will count toward it.
BATCH 01 / SIX INFECTED
Lurkers, Mutants and a Crawler Mutant
Keep the Crawler Mutant separate from the two ordinary Mutants. Both current NPC pages list two ordinary Mutants for this batch.
BATCH 02 / FIVE INFECTED
Risers, Slashers and Mikhail
Confirm this batch is active before fighting Mikhail. Having a previous Mikhail kill in your lifetime enemy record is not the same thing as completing the current sample request.
BATCH 03 / TWO BOSSES
Chimera and Gilbert
Tachyon's dialogue recommends bringing a squad for these targets. If you work with other players, arrange who needs the kill credit before the fight.
Why a kill might not count
The community achievements guide says you need the finishing blow for quest credit, including in a public server. Dealing some damage while a teammate finishes the target can leave your request incomplete. Recheck the active batch with Tachyon if your progress does not match your expectations.
¹ Death and leaving are different. Both NPC guides say dying does not erase the quest. Fandom documents progress as server-bound and says leaving resets it. Stay in the same server until the final hand-in; do not use a reconnect as a troubleshooting step.
This is community-documented behavior. The official GUINEA_PIG badge description only names completion of Tachyon's quest and does not specify kill attribution or reset mechanics.
Hand in the final samples
Return after Chimera and Gilbert, complete the final research dialogue and hand over the samples. The NPC guide describes Tachyon infecting your character with a guaranteed Controllable Infection outcome. Check that GUINEA_PIG has been awarded.
The infection event is not a promise of a permanent selectable class on future visits. Treat the badge and the immediate character effect as separate results.
If you finish the kills but get no reward
- Check whether all three batches were accepted and turned in.
- Check whether you personally received the final kill credit.
- Check whether you left or changed servers during the chain.
- Speak to Tachyon again and inspect your Roblox badge ownership.
Sources & verification
Checked September 23, 2026, using current NPC pages and the official badge API. No independent in-game run was performed.
- Roblox: GUINEA_PIG — official quest badge; enabled at the check.
- Miraheze: Elsher Tachyon — rank, appearance, dialogue, batch targets and infection outcome.
- Fandom: Elsher Tachyon — matching target counts and server-bound progress.
- Fandom: Achievements — public-server and finishing-blow guidance.