app.js

(function(){
  function handleClick(e) {
    e.preventDefault();
    e.stopPropagation();
    s = e.target.style;
    s.opacity = s.opacity === "" ? 0.5 : s.opacity * 0.5;
    console.log("I'm melting!");
    return false;
  }
  document.querySelectorAll('a').forEach((a) => a.onclick = handleClick);
})();

manifest.json

{
  "manifest_version": 2,
  "name": "Unclickable",
  "description": "Hahahahahahaha",
  "version": "0.1",
  "content_scripts": [
    {
      "matches": [
        "*://*/*"
      ],
      "js": [
        "app.js"
      ],
      "run_at": "document_end"
    }
  ]
}

Installation

git clone https://gist.github.com/d256e41255322df030b545cbc2fce918.git ~/Downloads/melting
open chrome://extensions/