https://www.reddit.com/user/jcunews1/

(function() {
  var im = new Image(),
    au, doneTurn,
    turnX, wid, hei, xDelta, yDelta,
    minXspd = 4, maxXspd = 8,
    maxYspd = 4, maxInus = 10,
    x, y;

  function newDeltas() {
    xDelta = Math.trunc(Math.random() * (maxXspd - minXspd)) + minXspd;
    yDelta = Math.trunc(Math.random() * ((maxYspd * 2) + 1)) - maxYspd;
  }
  function newMods() {
    doneTurn = false;
    turnX = Math.trunc(Math.random() * innerWidth)-wid;
    newDeltas();
    x = innerWidth;
    y = Math.trunc(Math.random() * (innerHeight + hei)) - hei;
  }

  window.inus = window.inus || 0;
  if(window.inus >= maxInus) return;
  if(!window.inus) {
    au = new Audio("https://omfgdogs.com/omfgdogs.mp3");
  }
  window.inus++;
  im.src = "http://i.imgur.com/ZgDxHDF.gif";
  im.style.cssText = "position:absolute;visibility:hidden;left:" + x + "px;top:" + y + "px";
  im.onload = function() {
    wid = im.width;
    hei = im.height;
    newMods();
    im.style.visibility = "";
    if(au) {
      au.loop = true;
      au.play();
    }
    setInterval(function() {
      x -= xDelta;
      y -= yDelta;
      if ((x < -wid) || (y < -hei) || (y > innerHeight)) {
        newMods();
      } else if (!doneTurn && (x <= turnX)) {
        doneTurn = true;
        newDeltas();
      }
      im.style.left = x + "px";
      im.style.top = y + "px";
    }, 25);
  };
  document.body.appendChild(im);
})()