The Chee holographic crystal was a piece of advanced Chee technology which was used to create holographic images. The Yeerks at one point got ahold of it, and intended to use it to lure in Human hosts. Erek enlisted the help of the Animorphs to help him steal it back.
Aximili-Esgarrouth-Isthill built a machine that, using the crystal, was able to "cloak" the group of Animorphs.
- The crystal appears in the TV series only.