animate.css/source/flippers/flipInX.css

@keyframes flipInX {
  0% {
    transform: perspective(400px) rotateX(90deg);
    opacity: 0;
  }

  40% {
    transform: perspective(400px) rotateX(-10deg);
  }

  70% {
    transform: perspective(400px) rotateX(10deg);
  }

  100% {
    transform: perspective(400px) rotateX(0deg);
    opacity: 1;
  }
}

.flipInX {
  backface-visibility: visible !important;
  animation-name: flipInX;
}