<button>Hover Me!</button>

@property --r {
  syntax: '<length-percentage>';
  initial-value: 0px;
  inherits: false
}
button {
  place-self: center;
  border: solid 2px #0001;
  padding: 0 1em;
  display: block;
  margin: 200px auto;
  border-radius: 2em;
  box-shadow: inset 1px 3px 1px #fff4;
  background: radial-gradient(circle at var(--x, 0%) var(--y, 0%), black calc(var(--r) - 1px), darkorange var(--r)) border-box;
  color: white;
  font: 1.5em/ 2.25 ubuntu, sans-serif;
  transition: --r .35s;

  &:hover { --r: 100% }
}

function update_position(e) {
  let _t = e.target;
  if(_t.tagName.match(/^button$/i)) {
    let r = _t.getBoundingClientRect();
    ['x', 'y'].forEach(c => 
      _t.style.setProperty(`--${c}`, `${e[`client${c.toUpperCase()}`] - r[c]}px`))
  }
}
addEventListener('mouseover', update_position);
addEventListener('mouseout', update_position)

<h1><span>Подпишись на телеграмм канал @code_ready</span></h1>

h1 {
  position: relative;
  width: 18em;
  margin: 3em auto;
  padding: .7em 0;
  font: normal 800 1.4em / 1.5 sans-serif;
  text-align: center;
  text-transform: uppercase;
}
span {
  box-shadow: inset 0 0 0 5em white, 0 0 0 .2em white;
}
h1:before {
  content: '';
  position: absolute;
  top: 0;
  right: 11%;
  bottom: 0;
  left: 11%;
  z-index: -1;
  border: 3px solid coral;
}

.loader-container {
  width:100px;
  height:100px;
  position: absolute;
  animation: scaleUp .5s linear;
  opacity: 0;
  transform: scale(0);
  .loader {
    background: #fff;
    animation: filterHue 2.5s linear infinite;
    height:100%;
    width: 100%;
  }
}
  @keyframes scaleUp {
  50% { transform: scale(0.5); opacity: 1; }
  100% { transform: scale(0.25) }
  }

window.addEventListener("mousemove", function (e) {
  var to_append = document.getElementsByClassName('loader-container')[0];
  var all = document.getElementsByClassName('loader-container');
  var parent_div = document.createElement('div');
  parent_div.className = "loader-container";
  var inner_div = document.createElement('div');
  inner_div.className = "loader";
  parent_div.appendChild(inner_div)
  var d = document.body.appendChild(parent_div);
  parent_div.style.left = (e.clientX - 50)+'px';
  parent_div.style.top = (e.clientY - 50)+'px';
  if(document.getElementsByClassName('loader-container').length > 50) {
    document.body.removeChild(to_append)
  }
});