Originally posted by lilshogun
Um no, Proteus would be a terrible match up against Thanos. Thanos with vast experience with Cosmic Cubes, IG, and the HOTU, has a WAY better lock on how Proteus' powers work than even Proteus does in reality warping. First of all Thanos was depicted in Thanos Quest as having no trouble with reality shifts. I believe his line was "Reality has a minimal effect on my being." In addition to that and having been in all sorts of realities, Thanos possessed the Reality gem which certainly provided him with some keen insights into how reality warping works. So having that knowledge. He would understand Proteus' powers better than Proteus.
I understand what you are saying, but it still wouldn't help if reality was turned against Thanos.
During his "Quest", Thanos was able to hold it together as he traveled from one dimension to another. But, nothing was permanent. And, it was environmental, not purposely turned against him as a weapon.
Against Proteus, reality would be turned against him.
Even if he understood what was happening, if he is turned into carbon dioxide, it isn't going to help him.
Or, if the way his brain actually works, was instantly changed. Without his mind, he can't even think his way out.
There is just too much Proteus can do. Where as, Thanos' options are limited.