Comet Tail

<div class="nuda-cur2-comet-tail">
  <span class="nuda-cur2-comet-tail__glow"></span>
  <span class="nuda-cur2-comet-tail__head"></span>
  <span class="nuda-cur2-comet-tail__label">Move your cursor</span>
</div>

/* Comet Tail — head and glow ease toward the pointer at different
   speeds, giving the head a soft trailing tail. */
(function () {
  document.querySelectorAll('.nuda-cur2-comet-tail').forEach(function (area) {
    area.addEventListener('mousemove', function (e) {
      var rect = area.getBoundingClientRect();
      area.style.setProperty('--x', (e.clientX - rect.left) + 'px');
      area.style.setProperty('--y', (e.clientY - rect.top) + 'px');
    });
  });
})();

.nuda-cur2-comet-tail {
  --x: 110px;
  --y: 60px;
  position: relative;
  width: 100%;
  max-width: 220px;
  height: 120px;
  margin: 0 auto;
  border-radius: 12px;
  background: #0a0a0a;
  border: 1px solid rgba(255,255,255,.08);
  overflow: hidden;
}

.nuda-cur2-comet-tail__glow {
  position: absolute;
  top: 0;
  left: 0;
  width: 36px;
  height: 36px;
  border-radius: 50%;
  background: radial-gradient(circle,rgba(228,255,84,.35),transparent 70%);
  filter: blur(4px);
  transform: translate(var(--x),var(--y)) translate(-50%,-50%);
  transition: transform .9s cubic-bezier(.16,1,.3,1);
  pointer-events: none;
}

.nuda-cur2-comet-tail__head {
  position: absolute;
  top: 0;
  left: 0;
  width: 10px;
  height: 10px;
  border-radius: 50%;
  background: #e4ff54;
  box-shadow: 0 0 10px 2px rgba(228,255,84,.7);
  transform: translate(var(--x),var(--y)) translate(-50%,-50%);
  transition: transform .35s cubic-bezier(.16,1,.3,1);
  pointer-events: none;
}

.nuda-cur2-comet-tail__label {
  position: absolute;
  bottom: 8px;
  left: 0;
  right: 0;
  text-align: center;
  color: #777;
  font-size: 11px;
  pointer-events: none;
}

@media (prefers-reduced-motion:reduce) {
  .nuda-cur2-comet-tail__glow,.nuda-cur2-comet-tail__head {
    transition: none;
  }
}