A Worbal's quills can be used as pens. They write with a luminescent ink the same color as it's bioluminescence. The ink is able to maintain it's brightness for years before fading and can be "recharged" by Worbal eletricity.
If a Worbal's quills falls out while turned off, the ink inside loses it's luminescent quality, but can still write.
The pens are rare outside Worbal systems and are often sold at a steep price.