The most scientifically plausible fictional substance

This video makes a tierlist of the four of the possibly most popular unobtainium varieties: Spice Melange from Frank Herbert's Dune, Unobtainium from James Cameron's Avatar, Vibranium from Marvel and Kryptonite from DC - all with an aim to determine, which one of them has the highest sci-fi hardness and thus has the highest chances to exist in reality.

Chapters:
0:00 Intro
0:41 Spice Melange
4:48 Cameron's Unobtainium
8:38 Vibranium
15:07 We don't talk about Kent
15:58 Kryptonite
22:01 Comic book varieties
23:07 Conclusions & Outro

Idea, research, script, pixelart, voice and editing by Surge
Music by Heepothesys
Gaming videos by MaxTeil and Surge
Sound editing advice and inspiration by Paula

*a lot of the information given in the video is based on the knowledge of the author, who has no special education in most of the topics he speaks on, so please take it with a grain of salt and leave a comment if you disagree