If the characters are camped or resting treat this encounter as "no encounter." Otherwise, the characters stumble upona large fungi patch growing in a damp cave or tunnel.
The fungi patch is diflicult terrain and consists of many common but inedible species of giant fungi.
Roll a d10 (I think this should be 20) and consult the Fungi Patch Discoveries table to determine what else the characters find here.
See "Fungi of the Underdark" in chapter 2 for more information an edible and exotic species of fungi.
Entries marked with an asterisk are further described after the table.
You rolled 6