Shadowkin cannot metabolize ethanol

[codeduck101]

📋 Description

Explain what the bug is and what you expected to happen instead.

this is a relatively old upstream bug noticed july 2026; see goobstation's Goob-Station/Goob-Station#6896
i have included additional testing notes in the notes section below

if a shadowkin has ethanol in their system, they cannot metabolize it. at high enough concentration, this causes infinite vomiting without lowering hunger/thirst and without actually dumping any stomach/bloodstream contents (the puddle does not exist and the bloodstream does not purge ethanol)
because the ethanol is not metabolized, it does not inflict ethanol poisoning (except for the infinite ghost vomit)
this cannot be fixed with the upgraded cybernetic heart or the cybernetic liver

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🔁 Steps to Reproduce

List the steps that consistently cause the issue.

1. be a shadowkin or acquire a shadowkin
2. (get the shadowkin to) drink either pure ethanol or an alcoholic beverage
3. watch in horror through the health analyzer that the ethanol is deadass not processing

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💥 Expected Behavior

Describe what you expected to happen.

the shadowkin should metabolize the ethanol at 0.05u/s, vomit reagents, and take ethanol poisoning damage over 15u ethanol

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🧠 Actual Behavior

Describe what actually happens.

ethanol does not metabolize or inflict poisoning damage. the shadowkin will vomit but not produce any reagent puddles

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📸 Screenshots / Videos

Attach any screenshots, clips, or logs that help show the problem.
1 min 51s

3 min 50s in (2 minutes passed)

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🗺️ Additional Details

Any other info that might help, like:

• Map / Round ID (if known)
• Game mode

found in-round after drinking from the bar as a shadowkin and having to go to med to get charcoal dumped into me

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🧩 Notes

Anything else that might help contributors reproduce or understand the issue.
Add any other context about the problem here.

vomiting itself is not broken because ipecac causes normal, expected vomiting (including on shadowkin)
this does not affect other low-metabolism chems like ammoniated mercury (0.15u/s), pyrazine/iron (0.1u/s), theobromine/anacea (0.05u/s), or formaldehyde/lead (0.03u/s)
i tested ethanol on humans and it is metabolized appropriately
i don't see where in code shadowkin should process ethanol any differently than other species
i tested about half of the other reagents in the game and the rest seem to work fine

[codeduck101]

PR'd upstream at Goob-Station/Goob-Station#7086

[codeduck101]

i want to keep this issue as i reported it, but during my bug testing with the above PR, i have found that yowie, hydrakin, chitinids, and people with cybernetic livers are also unable to metabolize ethanol

the issue is due to upstream converting ethanol from 0.5u/s to 0.05u/s and the liver prototypes not changing to compensate (as almost all species metabolized ethanol at 0.05u/s before upstream by setting their rate multipliers to 0.1, which was copied by species who used human as a template, which caused rounding issues from FixedPoint2 that resulted in the overall metabolism rate being set to 0.00)

[feistyfedora]

This is merged upstream
Will try to monitor when this gets to Omu to close this