I have defeated all of the main bosses except for Duke Fishron. But i have been searching for about a week and haven't seen a Truffle Worm! So i was wondering if there where any tips or tricks out there, since there's nothing on the Official Wiki.
Truffle Worms can actually be found in glowing mushroom biomes which are mostly underground. In order for them to spawn you need to have hard mode enabled so that means you need to defeat the Wall of Flesh first before they start spawning in glowing mushroom biomes. You can catch a Truffle Worm by using a bug net.