Edit in JSFiddle

<div class="trembling">
Don't kill me....
</div>
@keyframes trembling {
	0% {transform:translateX(0) rotate(0deg); background-color: #333;}
	20% {transform:translateX(-10px) rotate(-2deg);}
	40% {transform:translateX(10px) rotate(2deg);}
  50% {background-color: #e22;}
	60% {transform:translateX(-10px) rotate(-2deg); }
	80% {transform: translateX(10px) rotate(2deg);}
	100%{transform: translateY(0) rotate(0deg); background-color: #333;}
}

.trembling {
  height: 200px;
  font-family: sans-serif;
  font-weight: 900;
  font-size: 100px;
  text-align: center;
  color: #fff;
  line-height: 200px;
	animation: trembling 0.5s ease-in-out infinite;
}


.trembling:hover {
  animation-play-state: paused;
}