Disappearium

Disappearium is a substance in the Generation 1 continuity family.

Disappearium is a Cybertronian alloy that can render whatever item it is made of invisible, such as Optimus Prime's trailer/Combat Deck when Prime converts to robot mode.

Fiction

Generation 1

Generation 1 cartoon

After ordering a retreat, Optimus converted to his semi-truck mode. As he was doing so, his trailer emerged out of nothingness (as though it had uncloaked). The Ultimate Doom, Part 2

Note

• In the audio commentary for The Transformers: The Movie featuring Flint Dille, Susan Blu, and Nelson Shin, Dille gave a final explanation, during Optimus Prime's final attack against the Decepticons during the Battle of Autobot City, to what happens to Optimus Prime's trailer/Combat Deck when Prime converts to robot mode. According to Dille, the trailer is composed of disappearium, an alloy that has cloaking properties to it. And if you believe that, can I interest you in a case of dehydrated water?
• Of course, Prime's missing trailer/Combat Deck was a simple case of rushed animation that sacrificed minute details for meeting a deadline.
• At least Flint Dille didn't say that a wizard did it.