The TurtleBug is a rare and exclusive critter that is given to players who invite 25 or more friends to join Dizzywood.
If you are a Gold Explorer you can also get a TurtleBug through a Gold Explorer Mission.
When you found (or won) an Invite a Friend scroll, you can tell your friends the invitation code on it.
They can create a new Dizzywood account and insert the special code.