GoSquared Embedded Live Cat

livecat.js

function embedLiveCatTM() {
  var 📄 = document, 💅 = "style", ⬅ = "left", ⬇ = "bottom", 👍 = "translateX(-50%)", 🐳 = window,
      ↕ = "innerHeight", ↔ = "innerWidth", 😺 = 0, 🐈 = 🐳[↔] / 2, 🖖 = 0, 🎺 = 0, 👻 = "px",
      🔢 = Math, ⏲ = setInterval, 💩, 🐱 = 📄.createElement("img");
  🐱.setAttribute("src", "//static.gosquared.com/images/april/nes/cat_02.png");
  🐱[💅].height = 🐳[↕] / 20 * 10 + 👻;
  🐱[💅].position = "fixed";
  🐱[💅].transform = 👍;
  📄.body.appendChild(🐱);
  (function 🖌(){
    requestAnimationFrame(🖌);
    💩 = 0.01;
    🎺 = 🐈 * 💩 + 🎺 * (1 - 💩);
    💩 = 0.1;
    🖖 = 😺 * 💩 + 🖖 * (1 - 💩);
    🐱[💅][⬇] = 🖖 + 👻;
    🐱[💅][⬅] = 🎺 + 👻;
  })();
  ⏲(function(){
    🐈 = 🐳[↔] * (0.2 + 🔢.random() * 0.6);
    🐱[💅].transform = 🐈 < 🎺 ? 👍 + " scaleX(-1)" : 👍;
  }, 3000);
  ⏲(function(){
    var ❌ = 0.065 * 🐳[↕];
    😺 = -❌ - ❌ * 🔢.random();
  }, 200);
}

// now just call embedLiveCatTM() whenever you want a Live Cat on your site

For boring browsers that don't support emoji as JS identifiers, try something like this instead:

<code id="livecat"> function embedLiveCatTM(){ ... }</code>
<script>
  eval(document.getElementById('livecat').innerText.replace(/[\u1000-\uffff]/g, function(s){ return 'u'+s.charCodeAt(0); }));
</script>