Button

<div class="buttons">
  <button class="blob-btn">
    Кнопка
    <span class="blob-btn__inner">
      <span class="blob-btn__blobs">
        <span class="blob-btn__blob"></span>
        <span class="blob-btn__blob"></span>
        <span class="blob-btn__blob"></span>
        <span class="blob-btn__blob"></span>
      </span>
    </span>
  </button>
  <br/>
  <button class="blob-btn">
    Большая кнопка
    <span class="blob-btn__inner">
      <span class="blob-btn__blobs">
        <span class="blob-btn__blob"></span>
        <span class="blob-btn__blob"></span>
        <span class="blob-btn__blob"></span>
        <span class="blob-btn__blob"></span>
      </span>
    </span>
  </button>
</div>

<svg xmlns="http://www.w3.org/2000/svg" version="1.1">
  <defs>
    <filter id="goo">
      <feGaussianBlur in="SourceGraphic" result="blur" stdDeviation="10"></feGaussianBlur>
      <feColorMatrix in="blur" mode="matrix" values="1 0 0 0 0 0 1 0 0 0 0 0 1 0 0 0 0 0 21 -7" result="goo"></feColorMatrix>
      <feBlend in2="goo" in="SourceGraphic" result="mix"></feBlend>
    </filter>
  </defs>
</svg>
//Автор: Nikolay Talanov. @suez

*, *:before, *:after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

body {
  background: #333;
  font-family: "Open Sans", Helvetica, Arial, sans-serif;
}

.buttons {
  margin-top: 50px;
  text-align: center;
}

.blob-btn {
  z-index: 1;
  position: relative;
  padding: 20px 46px;
  margin-bottom: 30px;
  text-align: center;
  text-transform: uppercase;
  color: #0fe0f5;
  font-size: 16px;
  font-weight: bold;
  background-color: transparent;
  outline: none;
  border: none;
  transition: color 0.5s;
  cursor: pointer;
}
.blob-btn:before {
  content: "";
  z-index: 1;
  position: absolute;
  left: 0;
  top: 0;
  width: 100%;
  height: 100%;
  border: 6px solid #0fe0f5;
}
.blob-btn:after {
  content: "";
  z-index: -2;
  position: absolute;
  left: 9px;
  top: 9px;
  width: 100%;
  height: 100%;
  border: 6px solid #222;
  transition: all 0.3s 0.2s;
}
.blob-btn:hover {
  color: #222;
}
.blob-btn:hover:after {
  transition: all 0.3s;
  left: 0;
  top: 0;
}
.blob-btn__inner {
  z-index: -1;
  overflow: hidden;
  position: absolute;
  left: 0;
  top: 0;
  width: 100%;
  height: 100%;
}
.blob-btn__blobs {
  position: relative;
  display: block;
  height: 100%;
  filter: url("#goo");
}
.blob-btn__blob {
  position: absolute;
  top: 6px;
  width: 25%;
  height: 100%;
  background: #0fe0f5;
  border-radius: 100%;
  transform: translate3d(0, 150%, 0) scale(1.7);
  transition: transform 0.45s;
}
@supports (filter: url("#goo")) {
  .blob-btn__blob {
    transform: translate3d(0, 150%, 0) scale(1.4);
  }
}
.blob-btn__blob:nth-child(1) {
  left: 0%;
  transition-delay: 0s;
}
.blob-btn__blob:nth-child(2) {
  left: 30%;
  transition-delay: 0.08s;
}
.blob-btn__blob:nth-child(3) {
  left: 60%;
  transition-delay: 0.16s;
}
.blob-btn__blob:nth-child(4) {
  left: 90%;
  transition-delay: 0.24s;
}
.blob-btn:hover .blob-btn__blob {
  transform: translateZ(0) scale(1.7);
}
@supports (filter: url("#goo")) {
  .blob-btn:hover .blob-btn__blob {
    transform: translateZ(0) scale(1.4);
  }
}