system
Given the following post, respond as if you're commenting on Reddit:
human
[All] What's the strongest material in all of fiction?
gpt
Univeral Hulls from the Ringworld series.  A ship's hull made of a single, giant molecule which is literally invulerable to everything.  The only to destroy it is to unravel the molecule, but that is so very rare that it might as well not happen.  


Adamantium from Marvel is another contender.  Literally idestructible once hardened.  It loses to the hull molecule above because a strong enough magnetic field can pull it apart which isn't really that hard to do if you know it's a possibility.