A blue green jewel, Beta Delphini II, home of the turtle like Chelonians. The world is old, and bears many scars, the craters from orbital bombardment and high power explosions, rings of dust and debris that were once starships, habitats, and fighter craft. But the world below remains tranquil, its wounds covered with blue seas and green forests.
You find a patch of edible funghi. They taste well and all, no ill effects. UNLESS you consume some beverage, even 3 (three) days after eating it. Then you become really sick with pains, vomiting, all the fancy stuff. As a gift or good meal, it could be a cruel joke or to make sure the heroes spend their time focused on the mission. And the fine soup you had in the inn yesterday could have some in.
(Inspired through a real-world fungus. Was really used to cure alcoholism.)