html

<button class="blobs">
  <div class="blob1"></div>
  <div class="blob2"></div>
  <div class="blob3"></div>
  <p class="text">ぷるん</p>
</button>

<svg xmlns="http://www.w3.org/2000/svg" version="1.1">
  <defs>
    <filter id="goo">
      <feGaussianBlur in="SourceGraphic" stdDeviation="10" result="blur" />
      <feColorMatrix in="blur" mode="matrix" values="1 0 0 0 0  0 1 0 0 0  0 0 1 0 0  0 0 0 18 -7" result="goo" />
      <feBlend in="SourceGraphic" in2="goo" />
      <feComposite in="SourceGraphic" in2="goo" operator="atop" />
    </filter>
  </defs>
</svg>

scss

.blobs {
  filter: url(#goo);
  width: 200px;
  height: 100px;
  position: relative;
  margin: 100px auto;
  display: block;
  @include hover {
    .blob1 {
      animation: slime ease-in 1.6s forwards;
    }
    .blob2 {
      animation: rightDown ease-in 1.6s forwards;
    }
    .blob3 {
      animation: leftUp ease-in 1.6s forwards;
    }
    .text {
      animation: slime ease-in 1.6s forwards;
    }
  }
  .blob1 {
    background: #469536;
    width: 100%;
    height: 100%;
  }
  .blob2 {
    background: #469536;
    width: 80px;
    height: 80px;
    position: absolute;
    right: 10%;
    bottom: 10%;
    border-radius: 50%;
  }
  .blob3 {
    background: #469536;
    width: 80px;
    height: 80px;
    position: absolute;
    left: 10%;
    top: 10%;
    border-radius: 50%;
  }
  .text {
    color: #fff;
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    display: flex;
    align-items: center;
    justify-content: center;
  }
}

@keyframes slime {
  0% {
    transform: scale(1);
  }
  20% {
    transform: scale(1);
  }
  62% {
    transform: scale(1.05);
  }
  80% {
    transform: scale(1);
  }
}

@keyframes rightDown {
  0% {
    transform: translateX(0px);
    opacity: 1;
  }
  80% {
    transform: translateX(100px) translateY(100px) scale(0.6);
    opacity: 0.8;
  }
  100% {
    transform: translateX(140px) translateY(140px) scale(0.3);
    opacity: 0;
  }
}

@keyframes leftUp {
  0% {
    transform: translateX(0px);
    opacity: 1;
  }
  80% {
    transform: translateX(-100px) translateY(-100px) scale(0.6);
    opacity: 0.8;
  }
  100% {
    transform: translateX(-140px) translateY(-140px) scale(0.3);
    opacity: 0;
  }
}