JSFiddle - React, Tailwind, and code Playground

HTML

<div class="main">
    <div class="bubble"><div>
</div>

CSS

.main{width:100%;height:100%;position:relative;}
.bubble{width:100px;height:100px;background:rgba(0,0,0,0.2);border-radius:100%; position:absolute;top:0;left:-50px;}

JavaScript

function bubbles () {
	$(".bubble").animate({
		'background':"rgba(0,0,0,0.4)",
		'top':'-300px'
	}, 200);
}

bubbles();
setInterval(function() {
      bubbles();
}, 200);