Pilot Japan has broken the barrier between pencils and erasable gel pens! To highlight this fact, their newest FriXion pens have plastic bodies reminiscent of wooden pencils. These erasable gel pens write in vibrant gel colors that are unattainable with colored pencil lead. The pens are so erasable, you'll be amazed. An incredible selection of 24 colors is available. (more)
Here's the secret spy pen rub...
The ink is thermo-sensitive! Heat it. It disappears. Cool it. It reappears. All you need is a hair dryer and a refrigerator. (video)