SOURCE

function addPop() {
    const span = document.createElement('span');
    span.className = 'pop';
    const size = Math.floor((Math.random() * 25) + 1);
    const left = Math.floor((Math.random() * 25) + 43);
    const duraction = Math.floor((Math.random() * 5) + 1);
    const time = Math.floor((Math.random() * 5) + 1);

    span.style.width = size + 'px';
    span.style.height = size + 'px';
    span.style.left = left + '%';
    span.style.animation = `popMove ${time}s ${duraction}s linear infinite`;
    const myblock = document.getElementById('myblock');
    myblock.appendChild(span);
}

window.onload = function () {
    for (let i = 0; i < 20; i++) {
        addPop();
    }
}

<button onclick="addPop()">add pop </button>
<div class="box">
    <div class="myblock" id="myblock">
		<div class="sun">
            <div class="outCircle"></div>
            <div class="innerCircle"></div>
            <div class="text">15%</div>
        </div>
		<div class="field"></div>
        <div class="pop" style="width:20px; height: 20px; left: 24%; animation: popMove 5s 3s linear infinite;"></div>
	</div>

	<div class="battery">
		<div class="header"></div>
		<div class="charge"></div>
		<div class="cover">
			<div class="wave1"></div>
			<div class="wave2"></div>
		</div>
	</div>
</div>

* {
    padding: 0;
    margin: 0;
}

.box {
    width: 800px;
    height: 1800px;
    margin: 0 auto;
    background: black;
    position: relative;
    padding: 20px;
}

.battery {
    width: 200px;
    height: 320px;
    background: white;
    margin: 20px auto;
    border-radius: 15px 15px;
    position: relative;
}

.header {
    width: 50px;
    height: 20px;
    background: white;
    position: absolute;
    left: 50%;
    transform: translate(-50%, -20px);
    border-radius: 5px 5px 0 0;
}

.charge {
    position: absolute;
    left: 0;
    right: 0;
    bottom: 0;
    top: 95%;
    background: linear-gradient(#7abcff 0%, #7bacff 40%, #8cafff 100%);
    filter: hue-rotate(90deg);
    animation: charge 5s linear infinite;
}

@keyframes charge {
    0% {
        border-radius: 0 0 15px 15px;
    }
    95% {
        top: 5%;
        border-radius: 0 0 15px 15px;
    }
    100% {
        top: 0;
        border-radius: 15px;
        filter: hue-rotate(0deg);
    }
}

.cover {
    width: 100%;
    height: 100%;
    /* background: red; */
    border-radius: 15px;
    position: absolute;
    left: 0;
    top: 0;
    overflow: hidden;
}

.wave1 {
    width: 400px;
    height: 400px;
    background: rgba(255, 255, 255, 0.8);
    position: absolute;
    transform: translate(-25%, 0);
    border-radius: 40% 30%;
    animation: wave1 5s linear infinite;
}

.wave2 {
    width: 400px;
    height: 400px;
    background: rgba(255, 255, 255, 0.4);
    position: absolute;
    transform: translate(-25%, 0);
    border-radius: 30% 40%;
    animation: wave2 5s linear infinite;
}

@keyframes wave1 {
    0% {
        transform: translate(-25%, 0) rotate(0deg);
        bottom: 0%;
    }
    100% {
        transform: translate(-25%, 0) rotate(360deg);
        bottom: 100%;
    }
}

@keyframes wave2 {
    0% {
        transform: translate(-25%, 0) rotate(30deg);
        bottom: 0%;
    }
    100% {
        transform: translate(-25%, 0) rotate(360deg);
        bottom: 100%;
    }
}

.myblock {
    margin: 40px auto;
    /* background: gray; */
    width: 200px;
    height: 400px;
    position: relative;
    filter: contrast(15);
    animation: hueRotate 10s linear infinite;
}

.sun {
    position: relative;
    /* background: green; */
    width: 200px;
    height: 200px;
}

.outCircle {
    position: absolute;
    background: greenyellow;
    width: 150px;
    height: 150px;
    left: 50%;
    top: 50%;
    transform: translate(-50%, -50%);
    border-radius: 40% 42% 64% 47%;
    animation: circleRotate 10s linear infinite;
}

.innerCircle {
    position: absolute;
    background: black;
    width: 133px;
    height: 133px;
    left: 50%;
    top: 50%;
    transform: translate(-50%, -50%);
    border-radius: 50%;
}

@keyframes hueRotate {
    0% {
        filter: contrast(15) hue-rotate(0deg);
    }
    100% {
        filter: contrast(15) hue-rotate(360deg);
    }
}

@keyframes circleRotate {
    0% {
        transform: translate(-50%, -50%) rotate(0deg);
    }
    100% {
        transform: translate(-50%, -50%) rotate(360deg);
    }
}

.field {
    position: absolute;
    background: greenyellow;
    bottom: 0;
    width: 100px;
    height: 30px;
    border-radius: 65% 55% 25% 15%;
    left: 50%;
    transform: translate(-50%, 0);
}

.pop {
    position: absolute;
    background: greenyellow;
    /* width: 25px; */
    /* height: 25px; */
    border-radius: 50%;
    bottom: 0;
    /* left: 20%; */
    animation: popMove 5s 3s linear infinite;
}

@keyframes popMove {
    0% {
        bottom: 0;
    }
    100% {
        bottom: 220px;
    }
}

.text {
    position: absolute;
    color: white;
    font-size: 24px;
    left: 50%;
    top: 50%;
    transform: translate(-50%, -50%);
}