system
Given the following post, respond as if you're commenting on Reddit:
human
[DC] Superman is made of matter. Is he vulnerable to anti-matter? Couldn't an enemy that didn't care about the resulting extinction of humanity just plant a trap where Supes was tricked into touching a bunch of antimatter?

Braniac might be a good choice. Anyway, assume that the villain can obtain enough antimatter because that's how comics work.
gpt
You could, but it would take a heck of a setup to fool Superman. Let's assume for a minute that he's unable to recognize antimatter just by looking at it. Whenever dust or air from our universe touched the antimatter, there would be tiny but very intense bursts of energy that he would easily detect. To pull off the trick, you would need to isolate it from all matter whatsoever without using an elaborate containment system that tips him off to it being something dangerous.

The other problem you would face is the "water droplet on a griddle" effect. Superman's hand touches the antimatter, and it annihilates a small patch of skin off his palm. Right then and there, the resulting explosion would immediately blast him away in one direction and the antimatter away in another direction. Only a very small piece of Superman would actually cease to exist before he was blown back at extreme speed, so depending on which Superman this is, he might survive with a slightly hurt hand and a concussion.