In Jainism, there is debate about whether fungi (including mushrooms) are to be considered living beings that should be avoided. Many Jain scholars view mushrooms as living organisms, and some Jain practices recommend avoiding them because they are akin to plant life that may involve harm to life.

What happens if a Jain eats mushrooms unknowingly:

• Consequence of intention: Jain ethics emphasize ahimsa (non-harm) and the intention behind actions. If someone eats mushrooms unknowingly, the direct intention to harm a living being is absent, which reduces personal fault.
• Karma and repentance: Even when harm is unintentional, Jains may acknowledge the act and perform appropriate reflection or prayer. If one later learns that mushrooms were eaten, some may choose to confess or do light penance (as prescribed in their tradition) to cleanse the karmic nuance of the act.
• Tradition differences: There isn't a single universal rule across Digambar and Shwetambar traditions. Some communities avoid fungi, others may be more lenient, especially in cases of inadvertent consumption or uncertainty.

Guidance if this happens:

• Check current understanding with your local Jain teacher or community leader, since practices can vary by lineage and temple.
• Move forward with mindfulness: avoid mushrooms in the future if you are following a stricter interpretation; if you are uncertain, seek clarification from a trusted Jain authority in your tradition.
• If you discover you have eaten mushrooms by mistake, you can reflect on the intention, practice gratitude for the life of all beings, and consider a light devotional act or prayer as advised by your tradition.

If you’d like, tell me your specific Jain community (Digambar or Shwetambar) or the temple you follow, and I can tailor the guidance to that tradition.