- "This is heavy!"
- —The Quantum Mind Jar, quoting Marty McFly's famous expression
The Quantum Mind Jar is a technology from the 21st century that Emmett Brown came to possess at some point during his attempt to prevent a nuclear holocaust in 2045. It has an artificial intelligence with a female voice.
It is unknown how the Quantum Mind Jar was created, or how it came to be in Doc's possession. All that is known is that they worked together to prevent the hydrator, Nike MAG, hoverboard, and the Mr. Fusion from being available by 2015, in order to stop a nuclear holocaust from occurring on October 21, 2045.
Doc had meant to drop off the Quantum Mind Jar in 2075, but accidentally brought it back with him to 2015. The Quantum Mind Jar wanted to travel back to the future, but Doc refused, as he didn't want to risk changing history even more by attempting more time travel.
Personality and traits
The artificial intelligence of the Quantum Mind Jar was capable of using slang, as she remarked that the situation was "heavy" when there were two Emmett Browns present in 2015.