body {
  margin: 0;
  padding: 0;
}
.glitch {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: repeating-linear-gradient(90deg, #000 0%, #000 50%, #fff 50%, #fff 100%),
              repeating-linear-gradient(0deg, #000 0%, #000 50%, #fff 50%, #fff 100%);
  background-size: 50px 50px;
  animation: animate-bg 5s linear infinite;
}
@keyframes animate-bg {
  0% {
    background-position-y: 500px;
    background-blend-mode: darken;
  }
  25% {
    background-position-x: 500px;
    background-blend-mode: color;
  }
  50% {
    background-position-x: -1000px;
    background-blend-mode: difference;
  }
  75% {
    background-position-x: -5000px;
    background-position-y: 100px;
    background-blend-mode: multiply;
  }
  100% {
    background-position-y: -500px;
    background-blend-mode: hard-light;
  }
}