مفاجئة

<div class="col">
  <div class="container-1">
    <div class="btn btn-one">
      <span>BUTTON ONE</span>
    </div>
  </div>

  <div class="container-2">
    <div class="btn btn-two">
      <span>IDLE</span>
    </div>
  </div>

  <div class="container-3">
    <div class="btn btn-three">
      <span>BUTTON THREE</span>
    </div>
  </div>
</div>

<div class="col">
  <div class="container-4">
    <div class="btn btn-four">
      <span>BUTTON FOUR</span>
    </div>
  </div>

  <div class="container-5">
    <div class="btn btn-five">
      <span>BUTTON FIVE</span>
    </div>
  </div>

  <div class="container-6">
    <div class="btn btn-six">
      <span>BUTTON SIX</span>
    </div>
  </div>
</div>
 <style type="text/css">


@import 'https://fonts.googleapis.com/css?family=Open+Sans+Condensed:300';

/*
 FORMATTING FOR CODEPEN
*/


.col {
  height: 10%;
}

div[class*=container] {
  text-align: center;
  width: 100%;
  height: 33%;
  display: flex;
  justify-content: center;
  align-items: center;
}

.container-1 { background: #333; }
.container-2 { background: #4E598C; }
.container-3 { background: #8499B1; }
.container-4 { background: #9888A5; }
.container-5 { background: #7B6D8D; }
.container-6 { background: #565554; }

/*
 BUTTON STYLING
*/

.btn {
  position: relative;
  color: white;
  width: 256px;
  height: 64px;
  line-height: 64px;
  transition: all 0.3s;
  span {
    transition: all 0.3s;
    tranform: scale(1, 1);
  }
}

.btn::before, .btn::after {
  content: '';
  position: absolute;
  transition: all 0.3s;
  bottom: 0;
  left: 0;
  width: 100%;
  height: 100%;
  z-index: 1;
}

.btn-one::before {
  left: 4px;
  z-index: 1;
 
  opacity: 0;
  background: rgba(255, 255, 255, 0.1);
  transform: scale(0.1, 1);
}

.btn-one:hover::before {
  opacity: 1;
  transform: scale(1, 1);
}

.btn-one::after {
  transition: all 0.3s;
  border: 1px solid rgba(255, 255, 255, 0.5);
}

.btn-one:hover::after {
  transform: scale(1, .1);
  opacity: 0;
}

/* BTN TWO */
.btn-two::before, .btn-two::after {
  content: '';
  position: absolute;
  width: 100%;
  height: 100%;
  bottom: 0;
  left: 0;
  z-index: 1;
  transition: all 0.3s;
  border: 1px solid rgba(255, 255, 255, 0.5);
}

.btn-two:hover::after {
  animation-name: rotatecw;
  animation-duration: 2s;
}
.btn-two:hover::before {
  animation-name: rotateccw;
  animation-duration: 3s;
}
.btn-two:hover::after, .btn-two:hover::before {
  left: 96px;
  width: 64px;
 
  animation-iteration-count: infinite;
  animation-timing-function: linear;
}

@keyframes rotatecw {
    from {transform: rotate(0deg);}
    to {transform: rotate(360deg);}
}

@keyframes rotateccw {
    from {transform: rotate(0deg);}
    to {transform: rotate(-360deg);}
}

/* BTN THREE */
.btn-three::before {
  opacity: 0;
  background: rgba(255, 255, 255, 0.1);
  transform: scale(1, 0.1);
}

.btn-three:hover::before {
  opacity: 1;
  transform: scale(1, 1);
}

.btn-three::after {
  transition: all 0.3s;
  border: 1px solid rgba(255, 255, 255, 0.5);
}

.btn-three:hover::after {
  transform: scale(1, .1);
  opacity: 0;
}

/* BTN FOUR */

.btn-four:hover span {
  transform: scale(1.2, 1.2);
}

.btn-four::before {
  opacity: 0;
  background: rgba(255, 255, 255, 0.1);
  transform: scale(0.1, 0.1);
}

.btn-four:hover::before {
  opacity: 1;
  transform: scale(1, 1);
}

.btn-four::after {
  transition: all 0.3s;
  border: 1px solid rgba(255, 255, 255, 0.5);
}

.btn-four:hover::after {
  transform: scale(0, 0);
  opacity: 0;
}

/* BTN FIVE */
.btn-five::before {
  transition: transform 0.15s, 0.15s border-radius 0.15s;
  opacity: 0;
  background: rgba(255, 255, 255, 0.1);
  transform: scale(0.1, 0.1);
  border-radius: 50%;
}

.btn-five:hover::before {
  opacity: 1;
  transform: scale(1, 1);
  border-radius: 0;
}

.btn-five::after {
  transition: all 0.3s;
  border: 1px solid rgba(255, 255, 255, 0.3);
}

.btn-five:hover::after {
  opacity: 0;
}

/* BTN SIX */
.btn-six::before {
  opacity: 0;
  background: rgba(255, 255, 255, 0.1);
  transform: scale(1.3, 1.3);
}

.btn-six:hover::before {
  opacity: 1;
  transform: scale(1, 1);
}

.btn-six::after {
  transition: all 0.3s;
  border: 1px solid rgba(255, 255, 255, 0.5);
}

.btn-six:hover::after {
  transform: scale(0, 0);
  opacity: 0;
} 
 
</style>