<style>
.block {
margin: 50px;
height: 100px;
width: 100px;
background: #008000;
position: relative;
display: none;
}
.block::after {
content: '';
position: absolute;
left: 30px; top: -40px;
border: 20px solid transparent;
border-bottom: 20px solid green;
}
.toggle {
padding: 20px;
border: 1px solid #808080;
display: inline-block;
margin-left: 50px;
}
</style>
<div class="toggle">click me!</div>
<div class="block"></div>
<script src='https://cdnjs.cloudflare.com/ajax/libs/jquery/3.2.1/jquery.min.js'></script>
<script>$('.toggle').click(function(){
$('.block').slideToggle().css("overflow","visible");
})
</script>