Unpleasant Potion Side-effects

d12
1. Subject faints after use (1d6 minutes), unpredictable spells for remainder of day
2. Immobilizing gastro-intestinal distress after 3d6 minutes
3. Potion effect half-life: diminished effects linger following original duration
4. Potion "flashback": effects suddenly return for 1d6 minutes at random moment
5. Inverse effect follows original duration for equal period
6. Skin of imbiber flushes random colors for 1d6 hours
7. Hair grows uncontrollably for 1d6 days requiring constant maintenance
8. Teeth of subject rapidly decay: breath rendered intolerably foul, reversible only by magical dentistry
9. Instant addiction: subject goes to any length to procure lifetime supply of concoction or close facsimile
10. Abdominal bloating, discomfort and weight gain due to unknown effect on metabolism
11. Subject only able to emit frog-like croaks for 1d6 hours
12. Following effect duration, subject explodes into tiny fragments

Note: Use for potions of suspect manufacture or particularly ancient provenance