animate.css/source/flippers/flip.css

@keyframes flip {
  from {
    transform: perspective(400px) rotate3d(0, 1, 0, -360deg);
    animation-timing-function: ease-out;
  }

  40% {
    transform: perspective(400px) translate3d(0, 0, 150px) rotate3d(0, 1, 0, -190deg);
    animation-timing-function: ease-out;
  }

  50% {
    transform: perspective(400px) translate3d(0, 0, 150px) rotate3d(0, 1, 0, -170deg);
    animation-timing-function: ease-in;
  }

  80% {
    transform: perspective(400px) scale3d(.95, .95, .95);
    animation-timing-function: ease-in;
  }

  to {
    transform: perspective(400px);
    animation-timing-function: ease-in;
  }
}

.animated.flip {
  backface-visibility: visible;
  animation-name: flip;
}