Capture the Troll

From publisher blurb: Here's a challenge for you. Cross a monster-guarded lake, penetrate an immense cavern system, find the legendary fungoid forest, and capture a troll for the menagerie of Mingo the Moneyless. Either that, or be turned into a frog. Mingoh is a powerful wizard, utterly ruthless, and quite insane. Capturing a troll is actully not as dangerous as telling him why you wouldn't do this little errand for him.